“Steppe ancestry” step by step (2019): Mesolithic to Early Bronze Age Eurasia

yamnaya-gac-maykop-corded-ware-bell-beaker

The recent update on the Indo-Anatolian homeland in the Middle Volga region and its evolution as the Indo-Tocharian homeland in the Don–Volga area as described in Anthony (2019) has, at last, a strong scientific foundation, as it relies on previous linguistic and archaeological theories, now coupled with ancient phylogeography and genomic ancestry.

There are still some inconsistencies in the interpretation of the so-called “Steppe ancestry”, though, despite the one and a half years that have passed since we first had access to the closest Pontic–Caspian steppe source populations. Even my post “Steppe ancestry” step by step from a year ago is already outdated.

Admixture

The population selection process for models shown below included (1) plausibility of potential influences in the particular geographic and archaeological context; (2) looking for their clusters or particular samples in the PCA; and (3) testing with qpAdm for potential source populations that might have been involved in their development.

The results and graphics posted are therefore intended to simplistically show potential admixture events between populations potentially close to the actual sources of the target samples, whenever such mating networks could be supported by archaeology.

NOTE. This is an informal post and I am not a geneticist, so I am turning this flexibility to my advantage. If any reader is – for some strange reason – looking for a strict hypothesis testing, for the use of a full set of formal stats (as used e.g. in Ning et al. 2019 for Proto-Tocharians), and correctly redacted and peer-reviewed text, this is not the right place to find them.

spatial-pedigree-geographic-admixture
An example pedigree (a) of a focal individual sampled in the modern day, placed in its geographic context to make the spatial pedigree (b). Dashed lines denote matings, and solid lines denote parentage, with red hues for the maternal ancestors and blue hues for the paternal ancestors. In the spatial pedigree, each plane represents a sampled region in a discrete (nonoverlapping) generation, and each dot shows the birth location of an individual. The pedigree of the focal individual is highlighted back through time and across space. Image modified from Bradburd and Ralph (2019).

Despite the natural impulse to draw straight mixture trajectories (see e.g. Wang et al. 2019), simply adding or subtracting samples used for a PCA shows how the plot is affected by different variables (see e.g. what happens by including more South Asian samples to the PCA below), hence the need to draw curved arrows – not necessarily representing a sizable drift; at least not in recent prehistoric admixture events for which we have a reasonable chronological transect.

reich-arrows-admixture-neolithic-bronze-age
Representation of mixture events between European prehistoric peoples in the PCA. Image modified from David Reich‘s Who We Are and How We Got Here (2018).

Ethnolinguistic identification is a risky business that brings back memories of an evil use of cultural history and its consequences (at least in Western Europe, where this tradition was discontinued after WWII), but it seems necessary for those of us who want to find some confirmation of proposed dialectal schemes and language contacts.

Eneolithic Steppe vs. Steppe Maykop

First things first: I tested Bronze Age Eurasian peoples for the only two true steppe populations sampled to date, as potential sources of their “Steppe ancestry” – conventionally described as an EHG:CHG admixture, similar to that found in the first sampled Yamnaya individuals. I used the rightpops of Wang et al. (2018), but with a catch: since authors used WHG as a leftpop and Villabruna as a rightpop, and I find that a little inconsequential*, I preferred the strategy in Ning et al. (2019), contrasting as outgroup Eneolithic_Steppe (ca. 4300 BC) vs. Steppe_Maykop (ca. 3500 BC) when testing for WHG as a source population.

*WHG usually includes samples from a ‘western’ cluster (Loschbour and La Braña) and an ‘eastern’ cluster (Villabruna and Koros), see Lipson et al. (2017). Therefore, it doesn’t make much sense to include the same (or a very similar) population as a source AND an outgroup.

NOTE. For all other qpAdm analyses below, where WHG was not used as leftpop, I have used Villabruna as rightpop following Wang et al. (2019).

greater-caucasus-steppe-ancestry
Map of samples and sites mentioned in Wang et al. (2019), modified from the original to include labels of Eneolithic_Steppe and Steppe_Maykop samples. See PCA and ADMIXTURE grahpic for the identification of specific samples.

Results are not much different from what has been reported. In general, Yamnaya and related groups such as Bell Beakers and Steppe-related Chalcolithic/Bronze Age populations show good fits for Eneolithic_Steppe as their closest source for Steppe ancestry, and bad fits for Steppe_Maykop, whereas Corded Ware groups show the opposite, supporting their known differences.

This trend seems to be tempered in some groups, though, most likely due the influence of Samara_LN-like admixture in Circum-Baltic Late Neolithic and Eastern Corded Ware groups, and the influence of Anatolia_N/EEF-like admixture in Balkan and late European CWC or BBC groups. In fact, the more EEF-related ancestry in a populatoin, the less reliable these generic models (and even specific ones) seem to become when distinguishing the Steppe-related source.

NOTE. For more on this, see the discussion on Circum-Baltic Corded Ware peoples, and the discussion on Mycenaeans and their potential source populations.

These are just broad strokes of what might have happened around the Pontic–Caspian steppes before and during the Early Bronze Age expansions. The most relevant quest right now for Indo-European studies is to ascertain the chain of admixture events that led to the development and expansion of Indo-Uralic and its offshoots, Indo-European and Uralic.

mesolithic-eastern-europe-post-swiderian
Eastern European Mesolithic with the expansion of Post-Swiderian cultures. See full map.

A history of Steppe ancestry

This post is divided in (more or less accurate) chronological developments as follows:

  1. Hunter-gatherer pottery and the steppes
  2. Khvalynsk and Sredni Stog
  3. Post-Stog and Proto-Corded Ware
  4. Yamnaya and Afanasievo

1. Hunter-gatherer pottery and the steppes

I laid out in the ASOSAH book series the general idea – based on attempts to reconstruct the linguistic ancestor of Indo-Uralic – that Eurasiatic speakers might have expanded with the North-Eastern Techno-Complex that spread through north-eastern Europe during the warm period represented by the transition of the Palaeolithic to the Mesolithic.

If one were to trust the traditional migrationist view, a post-Swiderian population expanded from central-eastern Europe (potentially related originally to Epi-Gravettian peoples, represented by WHG ancestry) into north-eastern Europe, and then further east into the Trans-Urals, to then reappear in eastern Europe as a back-migration represented by the spread of hunter-gatherer pottery.

The marked shift from WHG-like towards EHG-related ancestry from Baltic Mesolithic (ca. 30%) to Combed Ware cultures (ca. 65%-100%) supports this continuous westward expansion, that is possibly best represented in the currently available sampling by the ‘south-eastern’ shift (CHG:ANE-related) of the hunter-gatherer from Lebyazhinka IV (5600 BC) relative to the older one from Sidelkino (9300 BC), both from the Samara region in the Middle Volga:

Mesolithic-Neolithic transition ca. 7000-6000 BC, with hunter-gatherer pottery groups spreading westwards. See full map.

From Anthony (2019):

Along the banks of the lower Volga many excavated hunting-fishing camp sites are dated 6200-4500 BC. They could be the source of CHG ancestry in the steppes. At about 6200 BC, when these camps were first established at Kair-Shak III and Varfolomievka, they hunted primarily saiga antelope around Dzhangar, south of the lower Volga, and almost exclusively onagers in the drier desert-steppes at Kair-Shak, north of the lower Volga. Farther north at the lower/middle Volga ecotone, at sites such as Varfolomievka and Oroshaemoe hunter-fishers who made pottery similar to that at Kair-Shak hunted onagers and saiga antelope in the desert-steppe, horses in the steppe, and aurochs in the riverine forests. Finally, in the Volga steppes north of Saratov and near Samara, hunter-fishers who made a different kind of pottery (Samara type) and hunted wild horses and red deer definitely were EHG. A Samara hunter-gatherer of this era buried at Lebyazhinka IV, dated 5600-5500 BC, was one of the first named examples of the EHG genetic type (Haak et al. 2015). This individual, like others from the same region, had no or very little CHG ancestry. The CHG mating network had not yet reached Samara by 5500 BC.

Given the lack of a proper geographical and chronological transect of ancient DNA from eastern European groups, and the discontinuous appearance of both R1b-M73 and R1b-M269 lineages on both sides of the Urals within the WHG:ANE cline, where EHG appears to have formed, it is impossible at this point to assert anything with enough degree of certainty. For simplicity purposes, though, I risked to equate the expansion of R1b-M73 in West Siberia as potentially associated with Micro-Altaic, and the expansion of hg. R1b-M269 with the spread of Indo-Uralic on both sides of the Urals.

NOTE. For incrementally speculative associations of languages with prehistoric cultures and their potential link to ancestry ± haplogroup expansions, you can check sections on Early Indo-Europeans and Uralians, Indo-Uralians, Altaic peoples, Eurasians, or Nostratians. I explained why I made these simplistic choices here.

While this identification of the Indo-Uralic expansion with hg. R1b is more or less straightforward for the Cis-Urals, given the available ancient DNA samples, it will be very difficult (if at all possible) to trace the migration of these originally R1b-M269-rich populations into Trans-Uralian groups that could eventually be linked to Yukaghir speakers. The sheer number of potential admixture events and bottlenecks in Siberian forest, taiga, and tundra regions since the Mesolithic until Yukaghirs were first attested is guaranteed to give more than one headache in upcoming years…

neolithic-steppes-samara-mariupol
Spread of hunter-gatherer pottery in eastern Europe ca. 6000-5000 BC. See full map.

The slight increase in WHG-related ancestry in Ukraine Neolithic groups relative to Mesolithic ones questions the arrival of this eastern influence in the north Pontic area, or at least its relevance in genomic terms, although the cluster formed is similar to the previous one and to Combed Ware groups – despite the Central European and Baltic influences in the north Pontic region – with some samples showing 0% change relative to Mesolithic groups.

ukraine-samara-mesolithic-neolithic-evolution
Structure and change in hunter-gatherer-related populations, from Mathieson et al. (2018). Inferred ancestry proportions for populations modelled as a mixture of WHG, EHG and CHG. Dashed lines show populations from the same geographic region. Percentages indicate proportion of WHG + EHG ancestry. Standard errors range from 1.5 to 8.3%.

NOTE. For more on Indo-Uralic and its reconstruction from a linguistic point of view, check out its dedicated section on ASOSAH, or the recently published (behind paywall) The Precursors of Proto-Indo-European, edited by Kloekhorst and Pronk, Brill (2019). Authors of specific chapters have posted their contributions to Academia.edu, where they can be downloaded for free.

2. Khvalynsk and Sredni Stog

The cluster formed by the three available samples of the Khvalynsk culture (early 5th millennium BC) might be described, as expected from its position in the PCA, as a mixture of EHG-like populations of the Middle Volga with CHG-like ancestry close to that represented by samples from Progress-2 and Vonyuchka, in the North Caucasus Piedmont (ca. 4300 BC):

This variable CHG-like admixture shown in the wide cluster formed by the available Khvalynsk-related samples support the interpretation of a recently created CHG mating network in Anthony (2019):

After 5000 BC domesticated animals appeared in these same sites in the lower Volga, and in new ones, and in grave sacrifices at Khvalynsk and Ekaterinovka. CHG genes and domesticated animals flowed north up the Volga, and EHG genes flowed south into the North Caucasus steppes, and the two components became admixed. After approximately 4500 BC the Khvalynsk archaeological culture united the lower and middle Volga archaeological sites into one variable archaeological culture that kept domesticated sheep, goats, and cattle (and possibly horses). In my estimation, Khvalynsk might represent the oldest phase of PIE.

steppe-ancestry-pca-neolithic-khvalynsk
Detail of the PCA of Eurasian samples, including Neolithic clusters with the hypothesized gene flows related to (1) the formation and (2) expansion of Khvalynsk and the (3) emergence of late Sredni Stog. See full image.

The richest copper assemblage found in all Khvalynsk burials belongs to an individual of hg. R1b-V1636 and intermediate Samara_HG:Eneolithic_Steppe ancestry, while full Eneolithic_Steppe-like admixture in the Middle Volga is represented by the commoner of Khvalynsk II, of hg. Q1. The finding of hg. R1b-V1636 in the North Caucasus Piedmont – and R1b-P297 in the Samara region (probably including Yekaterinovka) begs the question of the origin of hg. R1b-V1636 in the Khvalynsk community. Based on its absence in ancient samples from the forest zone, it is tempting to assign it to steppe hunter-gatherers down the Lower Volga and possibly to the east of it, who infiltrated the Samara region precisely during these population movements described by Anthony (2019).

Suvorovo-related samples from the Balkans, including the Varna and Smyadovo outliers of Steppe ancestry, are closely related to the Khvalynsk expansion:

Similarly, the ancestry of late Sredni Stog samples from Dereivka seem to be directly related to the expansion of Mariupol-like individuals over populations of Suvorovo-Novodanilovka-like admixture, as suggested by the resurgence of typical Ukraine Neolithic haplogroups, the shift in the PCA, and the models of Eneolithic_Steppe vs. Steppe_Maykop above:

#EDIT (11 Nov 2019): In fact, the position of the unpublished Greece_Neolithic outlier that appeared in the Wang et al. (2018) preprint (see full PCA and ADMIXTURE) show that the expanding Suvorovo chiefs from the Balkans formed a tight cluster close to the two published outliers with Steppe ancestry from Bulgaria.

The Ukraine_Neolithic outlier, possibly a Novodanilovka-related sample suggests, based on its position in the PCA close to the late Trypillian outlier of Steppe-related ancestry, that Ukraine_Eneolithic samples from Dereivka are a mixture of Ukraine_Neolithic and a Novodanilovka-like community similar to Suvorovo.

The Trypillian_Eneolithic-like admixture found among Proto-Corded Ware peoples (see below) would then feature potentially a small Steppe_Eneolithic-like component already present in the north Pontic area, too.

pca-suvorovo-novodanilovka-khvalynsk-trypillia-greece-ukraine-neolithic-outlier
Image modified from Wang et al. (2018). Samples projected in PCA of 84 modern-day West Eurasian populations (open symbols). Previously known clusters have been marked and referenced. Marked and labelled are the Balkan samples referenced in this text An EHG and a Caucasus ‘clouds’ have been drawn, leaving Pontic-Caspian steppe and derived groups between them. See the original file here.

Furthermore, whereas Anthony (2019) mentions a long-lasting predominance of hg. R1b in elite graves of the Eneolithic Volga basin, not a single sample of hg. R1a is mentioned supporting the community formed by the Alexandria individual, supposedly belonging to late Sredni Stog groups, but with a Corded Ware-like genetic profile (suggesting yet again that it is possibly a wrongly dated sample).

NOTE. A lack of first-hand information rather than an absence of R1a-M417 samples in the north Pontic forest-steppes would not be surprising, since Anthony is involved in the archaeology of the Middle Volga, but not in that of the north Pontic area.

eneolithic-pontic-caspian-steppe-khvalynsk-novodanilovka-suvorovo
Khvalynsk expansion through the Pontic–Caspian steppes in the early 5th millennium BC. See full map.

3. Post-Stog and Proto-Corded Ware

The origin of the Pre-Corded Ware ancestry is still a mystery, because of the heterogeneity of the sampled groups to date, and because the only ancestral sample that had a compatible genetic profile – I6561 from Alexandria – shows some details that make its radiocarbon date rather unlikely.

The most likely explanation for the closest source population of Corded Ware groups, found in the three core samples of Steppe_Maykop and in Trypillian Eneolithic samples from the first half of the 4th millennium BC, is still that a population of north Pontic forest-steppe hunter-gatherers hijacked this kind of ancestry, that was foreign to the north Pontic region before the Late Eneolithic period, later expanding east and west through the Podolian–Volhynian upland, due to the complex population movements of the Late Eneolithic.

NOTE. The idea of Trypillia influencing the formation of the Steppe_MLBA ancestry proper of Uralic peoples has been around for quite some time already, since the publication of Narasimhan et al. (2018) (see here or here).

steppe-ancestry-pca-corded-ware-bronze-age
Detail of the PCA of Eurasian samples, including Corded Ware groups and related clusters, as well as outliers, with hypothesized gene flows related to the (1) formation and (2) initial expansion of Pre-Corded Ware ancestry, as well as (3) later regional admixture events. See full image.

The specifics of how the Proto-Corded Ware community emerged remain unclear at this point, despite the simplistic description by Rassamakin (1999) of the Late Eneolithic north Pontic population movements as a two-stage migration of 1) late Trypillian groups (Usatovo) west → east, and (2) Late Maykop–Novosvobodnaya east → west. So, for example, Manzura (2016) on the Zhivotilovka “cultural-historical horizon” (emphasis mine):

Indeed, the very complex combination of different cultural traits in the burial sites of the Zhivotilovka type is able to generate certain problems in the search for the origins of this phenomenon. The only really consistent attribute is the burial rite in contracted position on the left or right side. Yu. Rassamakin is correct in asserting that this position of the deceased can be considered as new in the North Pontic region (Rassamakin 1999, 97). However, this opinion can be accepted only partially for the territory between Dniester and Lower Don. This position is well known in the Usatovo culture in the Northwest Pontic region, although skeletons on the right side are evidenced there only in double burials, whereas single burials contain the deceased only in a contracted position on the left side. On the other hand, the southern and western orientation of the deceased, which is one of the main burial traits of the Zhivotilovka type, is not characteristic of the Usatovo culture. Nevertheless, it is possible to suppose that at least part of the Usatovo population could have played a part in the formation of the cultural type under consideration here. One aspect of this cultural tradition, for instance, could be represented by skeletons on the left side and oriented in north-eastern and eastern directions.

Especially close ties can be traced between the Zhivotilovka and Maykop-Novosvobodnaya traditions, as exemplified by similar burial customs and various grave goods. It is beyond any doubt that the Maykop-Novosvobodnaya population was actively involved in the spread of the main Zhivotilovka cultural traits. The influence of North Caucasian traditions can be well observed, at least as far as the Dnieper Basin, but farther west influence is not manifested pronouncedly. The role of cultural units situated between the Dniester and Don rivers in the process of emergence of the Zhivotilovka type looks somewhat vague. Now, it can be quite confidently asserted that at the end of the 4th millennium BC this territory was settled by migrants from the North Caucasus and Carpathian-Dniester region. This event in theory had to stimulate cultural transformations in the Azov-Black Sea steppes and, thus, bearers of local cultural traditions perhaps could have participated in forming the culture under consideration. In any event, the Zhivotilovka type can be regarded as a complex phenomenon that emerged within the regime of intensive cultural dialogue and that it absorbed totally diff erent cultural traditions. The spread of the Zhivotilovka graves across the Pontic steppes from the Carpathians to the Lower Don or even to the Kuban Basin clearly signalizes a rapid dissolution of former cultural borders and the beginning of active movements of people, things and ideas over vast territories.

zhivotilovka-horizon-north-pontic-area

What were the factors or reasons that could have provoked this event? In the beginning of the second half of the 4th millennium BC two advanced cultural centers emerged in the south of Eastern Europe. These were the Maykop-Novosvobodnaya and Usatovo cultures, which in spite of their separation by great distances were structurally very alike. This is expressed in similar monumental burial architecture, complex burial rites, even the composition of grave goods, developed bronze metallurgy, high standards of material culture, etc. Both cultures in a completely formed state exemplify prosperous societies with a high level of economic and social organization, which can correspond to the type of ranked or early complex societies. Normally, the social elite in such polities tends to rigidly control basic domains social, economic and spiritual life using different mechanisms, even open compulsion (Earle 1987, 294-297). To some extent similar social entities can be found at this moment in the forest-steppe zone of the Carpathian-Dniester region, as reflected by the well organized settlement of Brânzeni III and the Vykhatitsy cemetery (Маркевич 1981; Дергачев 1978). In spite of their complex character, such societies represent rather friable structures, which could rapidly disintegrate due to unfavourable inner or external factors.

The societies in question emerged and existed during a time of favourable natural climatic conditions, which is considered to be a transitional period from the Atlantic to the Subboreal period, lasting approximately from 3600 to 3300 cal BC, or a climatic optimum for the steppe zone (Иванова и др. 2011, 108; Спиридонова, Алешинская 1999, 30-31). These conditions to a large degree could guarantee a stable exploitation of basic resources and support existing social hierarchies. However, after 3300 cal BC significant climatic changes occurred, accompanied by an increasing aridization and fall in temperature. This event is usually termed the “Piora oscillation” or “Rapid Climatic Event”, and is regarded as having been of global character (Magny, Haas 2004). These rapid changes could have seriously disturbed existing economic and social relations and finally provoked a similar rapid disintegration of complex social structures. In this case the sites of the Zhivotilovka type could represent mere fragments of former prosperous societies, which under conditions of the absence of centralized social control and stable cultural borders tried to recombine social and economic ties. However, the population possessed the necessary social experience and important technological resources, such as developed stock-breeding based on the breeding of small cattle and wheeled transport, so they were ready for opening new territories in their search for a better life.

maykop-trypillia-intrusion-steppes
Disintegration, migration, and imports of the Azov–Black Sea region. First migration event (solid arrows): Gordineşti–Maikop expansion (groups: I – Bursuchensk; II – Zhyvotylivka; III – Vovchans’k; IV – Crimean; V – Lower Don; VI – pre-Kuban). Second migration event (hollow arrows): Repin expansion. After Rassamakin (1999), Demchenko (2016).

For more on chronology and the potentially larger, longer-lasting Zhivotilovka–Volchansk–Gordineşti cultural horizon and its expansion through the Podolian–Volhynian upland, read e.g. on the Yampil Complex in the latest volume 22 of Baltic-Pontic Studies (2017):

In the forest-steppe zone of the North-West Pontic area, important data concerning the chronological position of the Zhivotilovka-Volchansk group have been produced by the exploration of the Bursuceni kurgan, which is still awaiting full publication [Yarovoy 1978; cf. also Demcenko 2016; Manzura 2016]. Burials linked with the mentioned group were stratigraphically the eldest in the kurgan, and pre-dated a burial in the extended position and [Yamnaya culture] graves. Two of these burials (features 20 and 21) produced radiocarbon dates falling around 3350-3100 BC [Petrenko, Kovaliukh 2003: 108, Tab. 7]. Similar absolute age determinations were obtained for Podolia kurgans at Prydnistryanske [Goslar et al. 2015]. These dates, falling within the Late Eneolithic, mark the currently oldest horizon of kurgan burials in the forest-steppe zone of the North-West Pontic area. The Podolia graves linked with other, older traditions of the steppe Eneolithic seem to represent a slightly later horizon dated to the transition between the Late Eneolithic and Early Bronze Age.

The presence on the left bank of the Dniester River of kurgans associated with the Eneolithic tradition, which at the same time reveals connections with the Gordineşti-Kasperovce-Horodiştea complex, raises questions about the western range of the new trend in funerary rituals, and its potential connection with the expansion of the late Trypilia culture to the West Podolia and West Volhynia Regions. The data potentially suggesting the attribution of kurgans from the upper Dniester basin to this period is patchy and difficult to verify [e.g. Liczkowce – see Sulimirski 1968: 173]. In this context, the discovery of vessels in the Gordineşti style in a kurgan at Zawisznia near Sokal is inspiring [Antoniewicz 1925].

zhivotilovka-volchansk-burial-podolia
Burials representing funerary traditions of Zhivotilovka-Volchansk group in Podolie kurgans: 1 – Porohy, grave 3A/7, 2 – Kuzmin, grave 2/2 [after Klochko et al. 2015b, Bubulich, Khakhey 2001]

Another interesting aspect of potential source populations, in combination with those above for Eneolithic_Steppe vs. Steppe_Maykop, are groups with worse fits for Steppe_Maykop_core, which include Potapovka and Srubnaya, as reported by Wang et al. (2018), but also Sintastha_MLBA (although not Andronovo). This is compatible with the long-term admixture of Abashevo chiefs dominating over a majority of Poltavka-like herders in the Don-Volga-Ural steppes during the formation of the Sintashta-Potapovka-Filatovka community, also visible in the typical Yamnaya lineages and Yamnaya-like ancestry still appearing in the region centuries after the change in power structures had occurred.

NOTE. If you feel tempted to test for mixtures of Khvalynsk_EN, Eneolithic_Steppe, Yamnaya, etc. as a source population for Corded Ware, go for it, but it’s almost certain to give similar ‘good’ fits – whatever the model – in some Corded Ware groups and not in others. It is still unclear, as far as I know, how to formally distinguish a mixture of Corded Ware-related from a Yamnaya-related source in the same model, and the results obtained with a combination of Steppe_Maykop-related + Eneolithic_Steppe-related sources will probably artificially select either one or the other source, as it probably happened in Ning et al. (2019) with Proto-Tocharian samples (see qpAdm values) that most likely had a contribution of both, based on their known intense interactions in the Tarim Basin.

eneolithic-pontic-caspian-steppes-east-europe
Expansion of north Pontic cultures and related groups during the Late Eneolithic. See full map.

#EDIT (22 NOV 2019): New preprint Gene-flow from steppe individuals into Cucuteni-Trypillia associated populations indicates long-standing contacts and gradual admixture, by Immel et al. bioRxiv (2019), on Gordinești samples from Moldova ca. 3500-3100 BC. Relevant excerpts (emphasis mine):

A principal component analysis of the four Moldova females together with previously published data sets of ancient Eurasians showed that Gordinești, Pocrovca 1 and Pocrovca 3 grouped with later dating Bell Beakers from Germany and Hungary close to the four CTC males from Verteba, while Pocrovca 2 fell into the LBK cluster next to Neolithic farmers from Anatolia and Starčevo individual.

When looking at various proxies for steppe-related ancestry (Yamnaya Samara, Ukraine Mesolithic, Caucasian hunter-gatherer (CHG), Eastern hunter gatherer (EHG)), we did not observe any significant difference in genetic influx from either Yamnaya Samara, EHG or Ukraine Mesolithic. However, relative to CHG, we detected a substantial shift towards Yamnaya Samara steppe-related ancestry. Consequently, Yamnaya Samara, Ukraine Mesolithic and EHG appear to be equally suitable proxies for steppe-related ancestry in the Moldovan CTC individuals.

We did not obtain feasible models when running qpAdm on the X-chromosome in order to test for male-biased admixture from hunter-gatherers or individuals with steppe-related ancestry.

It is not surprising that Gordinești, Pocrovca 1 and Pocrovca 3 showed genetic affinities with later dating Bronze Age or Bell Beaker individuals. The common link among them is the considerable steppe-related ancestry, which each group likely received independently from different parental populations.

pca-trypillia-verteba-pocrovka-gordinesti
Principal component analysis of the CTC individuals from Moldova (Gordinești, Pocrovca 1, Pocrovca 2, Pocrovca 3) in red and the CTC individuals from Verteba Cave (I1926, I2110, I2111, I3151) in blue together with 23 selected ancient populations/individuals projected onto a basemap of 58 modern-day West Eurasian populations (not shown). HG=hunter-gatherer, LBK=Linearbandkeramik, PU=Proto-Unetice, TRB=Trichterbecher (Funnel Beaker Culture, FBC). PC1 is shown on the x-axis and PC2 on the y-axis.

4. Yamnaya and Afanasievo

I don’t think it makes much sense to test for GAC (or Iberia_CA, for that matter) as Wang et al. (2019) did, given the implausibility of them taking part in the formation of late Repin during the mid-4th millennium BC around the Don-Volga interfluve (represented by its offshoots Yamnaya and Afanasievo), whether these or other EEF-related populations show ‘better’ fits or not. Therefore, I only tested for more or less straightforward potential source populations:

steppe-ancestry-pca-yamnaya-hungary-bulgaria-vucedol
Detail of the PCA of Eurasian samples, including Yamnaya groups and related clusters, as well as outliers, with hypothesized gene flows related to its (1) formation and (2) expansion. Also included is the inferred position of the admixed sample Yamnaya_Hungary_EBA1. See full image.

Quite unexpectedly – for me, at least – it appears that Afanasievo and Yamnaya invariably prefer Khvalynsk_EN as the closest source rather than a combination including Eneolithic_Steppe directly. In other words, late Repin shows largely genetic continuity with the Steppe ancestry already shown by the three sampled individuals from the Khvalynsk II cemetery, in line with the known strong bottlenecks of Khvalynsk-related groups under R1b lineages, visible also later in Afanasievo and Yamnaya and derived Indo-European-speaking groups under R1b-L23 subclades.

NOTE. This explains better the reported bad fits of models using directly Eneolithic_Steppe instead of Khvalynsk_EN for Afanasievo and Yamnaya Kalmykia, as is readily evident from the results above, instead of a rejection of an additional contribution to an Eneolithic_Steppe-like population, as I interpreted it, based on Anthony (2019).

repin-zhivotilovka-north-pontic-steppe
Map of major sites of the Zhivotilovka-Volchansk group (A) and Repin culture (B), by Rassamakin (see 1994 and 2013). (A) 1 – Primorskoye; 2 – Vasilevka; 3 – Aleksandrovka; 4 – Boguslav; 5 – Pavlograd; 6 – Zhivotilovka; 7 – Podgorodnoye; 8 – Novomoskovsk; 9- Sokolovo; 10 – Dneprelstan; 11- Razumovka; 12 – Pologi; 13 – Vinogradnoye; 14 – Novo-Filipovka; 15 – Volchansk; 16 – Yuryevka; 17 – Davydovka; 18 – Novovorontsovka; 19 – Ust-Kamenka; 20 – Staroselye; 21- Velikaya Aleksandrovka; 22- Kovalevka; 23 – Tiraspol; 24 – Cura-Bykuluy; 25 – Roshkany; 26 – Tarakliya; 27 – Kazakliya; 28 – Bolgrad; 29 – Sarateny; 30 – Bursucheny; 31 – Novye Duruitory; 232 – Kosteshty. (B) 1 – Podgorovka; 2 – Aleksandria; 3 – Volonterovka; 4 – Zamozhnoye; 5 – Kremenevka; 6 – Ogorodnoye; 7 – Boguslav; 8 – Aleksandrovka; 9 – Verkhnaya Mayevka; 10 – Duma Skela; 11 – Zamozhnoye; 12 – Mikhailovka II.

This might suggest that the Steppe ancestry visible in samples from Progress-2 and Vonyuchka, sharing the same cluster with the Khvalynsk II cemetery commoner of hg. Q1, most likely represents North Caspian or Black Sea–Caspian steppe hunter-gatherer ancestry that increased as Khvalynsk settlers expanded to the south-west towards the Greater Caucasus, probably through female exogamy. That would mean that Steppe_Maykop potentially represents the ‘original’ ancestry of steppe hunter-gatherers of the North Caucasus steppes, which is also weakly supported by the available similar admixture of the Lola culture. The chronology, geographical location and admixture of both clusters seemed to indicate the opposite.

eneolithic-steppe-maykop-ehg-chg-ag2
Modelling results for the Steppe and Caucasus cluster. Additional ‘eastern’ AG-Siberian gene flow in Steppe Maykop relative to Eneolithic Steppe. From Wang et al. (2019).

Due to the limitations of the currently available sampling and statistical tools, and barring the dubious Alexandria outlier, it is unclear how much of the late Trypillian-related admixture of late Repin (as reflected in Yamnaya and Afanasievo) corresponds to late Trypillian, Post-Stog, or Proto-Corded Ware groups from the north Pontic area. A mutual exchange suggestive of a common mating network (also supported by the mixed results obtained when including Khvalynsk_EN as source for early Corded Ware groups) seem to be the strongest proof to date of the Late Proto-Indo-European – Uralic contacts reflected in the period when post-laryngeal vocabulary was borrowed (with some samples predating the merged laryngeal loss), before the period of intense borrowing from Pre- and Proto-Indo-Iranian.

Between-group differences of Yamnaya samples are caused – like those between Corded Ware groups – by the admixture of a rapidly expanding society through exogamy with regional populations, evidenced by the inconstant affinities of western or southern outliers for previous local populations of the west Pontic or Caucasus area. This explanation for the gradual increase in local admixture is also supported by the strong, long-term patrilineal system and female exogamy practiced among expanding Proto-Indo-Europeans.

chalcolithic-early-bronze-yamnaya-corded-ware-vucedol
Groups of the Yamnaya culture and its western expansion after ca. 3100 BC, and Corded Ware after ca. 2900 BC See full map.

Bell Beakers and Mycenaeans

This Eneolithic_Steppe ancestry is also found among Bell Beaker groups (see above). More specifically, all Bell Beaker groups prefer a source closest to a combination of Yamnaya from the Don and Baden LCA individuals from Hungary, rather than with Corded Ware and GAC, despite the quite likely admixture of western Yamnaya settlers with (1) south-eastern European (west Pontic, Balkan) Chalcolithic populations during their expansion through the Lower Danube and with (2) late Corded Ware groups (already admixed with GAC-like populations) during their expansion as East Bell Beakers:

Similarly, Mycenaeans show good fits for a source close to the Yamnaya outlier from Bulgaria:

steppe-ancestry-pca-bell-beakers-mycenaeans
Detail of the PCA of Eurasian samples, including Bell Beaker and Balkan EBA groups and related clusters, as well as outliers, including ancestral Yamnaya samples from Hungary (position inferred) and Bulgaria. Also marked are Minoans, Mycenaeans and Armenian BA samples. See full image.

You can read more on Yamnaya-related admixture of Bell Beakers and Mycenaeans, and on Afanasievo-related admixture of Iron Age Proto-Tocharians.

Conclusion

The use of the concept of “Yamnaya ancestry”, then “Steppe ancestry” (and now even “Yamnaya Steppe ancestry“?) has already permeated the ongoing research of all labs working with human population genomics. Somehow, the conventional use of Yamnaya_Samara samples opposed to a combination of other ancient samples – alternatively selected among WHG, EHG, CHG/Iran_N, Anatolia_N, or ANE – has spread and is now unquestionably accepted as one of the “three quite distinct” ancestral groups that admixed to form the ancestry of modern Europeans, which is a rather odd, simplistic and anachronistic description of prehistory…

It has now become evident that authors involved with the Proto-Indo-European homeland question – and the tightly intertwined one of the Proto-Uralic homeland – are going to dedicate a great part of the discussion of many future papers to correct or outright reject the conclusions of previous publications, instead of simply going forward with new data.

The most striking argument to mistrust the current use of “Steppe ancestry” (as an alternative name for Yamnaya_Samara, and not as ancestry proper of steppe hunter-gatherers) is not the apparent difference in direct Eneolithic sources of Steppe ancestry for Corded Ware and Yamnaya-related peoples – closer to the available samples classified as Steppe_Maykop and Eneolithic_Steppe, respectively – or their different evolution under marked Y-DNA bottlenecks.

It is not even the lack of information about the distant origin of these Pontic–Caspian steppe hunter-gatherers of the 5th and 4th millennium BC, with their shared ancestral component potentially separated during the warmer Palaeolithic-Mesolithic transition, when the steppes were settled, without necessarily sharing any meaningful recent history before the formation of the Proto-Indo-Uralic community.

NOTE. I have raised this question multiple times since 2017 (see e.g. here or here).

The most striking paradox about simplistically misinterpreting “Steppe ancestry” as representative of Indo-European expansions is that those sub-Neolithic Pontic–Caspian steppe hunter-gatherers that had this ancestry in the 6th millennium BC were probably non-Indo-European-speaking communities, most likely related to the North(West) Caucasian language family, based on the substrate of Indo-Anatolian that sets it apart from Uralic within the Indo-Uralic trunk, and on later contacts of Indo-Tocharian with North-West Caucasian and Kartvelian, the former probably represented by Maykop and its contact with the Repin and early Yamnaya cultures.

NOTE. For more on this, see Allan Bomhard’s recent paper on the Caucasian substrate hypothesis and its ongoing supplement Additional Proto-Indo-European/Northwest Caucasian Lexical Parallels.

steppe-ancestry-racimo
“Spatiotemporal kriging of YAM steppe ancestry during the Holocene, using 5000 spatial grid points. The colors represent the predicted ancestry proportion at each point in the grid.” Image with evolution from ca. 2800 BC until the present day, modified from Racimo et al. (2019). The Copenhagen group considers the expansion of this component as representative of expanding Indo-Europeans…

This kind of error happens because we all – hence also authors, peer reviewers, and especially journal editors – love far-fetched conclusions and sensational titles, forgetting what a paper actually shows and – always more importantly in scientific reports – what it doesn’t show. This is particularly true when more than one field is involved and when extraordinary claims involve aspects foreign to the journal’s (and usually the own authors’) main interests. One would have thought that the glottochronological fiasco published in Science in 2012 (open access in PMC) should have taught an important lesson to everyone involved. It didn’t, because apparently no one has felt the responsibility or the shame to retract that paper yet, even in the age of population genomics.

If anything, the excesses of mathematical linguistics – using computational methods to try and reconstruct phylogenetic trees – have perpetuated a form of misunderstood Scientism which blindly relies on a simple promise made by authors in the Materials and Method section (rarely if ever kept beyond it) to use statistics rather than resorting to the harder, well-informed, comprehensive reasoning that is needed in the comparative method. After all, why should anyone invest hundreds of hours (or simply show an interest in) learning about historical linguistics, about ancient Indo-European or Uralic languages, carefully argumenting and discussing each and every detail of the reconstruction, when one can simply rely on the own guts to decide what is Science and what isn’t? When one can trust a promise that formulas have been used?

The conservative, null hypothesis when studying prehistoric Eurasian samples related to evolving cultures was universally understood as no migration, or “pots not people” (as most western archaeologists chose to believe until recently), whereas the alternative one should have been that there were in fact migration events, some of them potentially related to the expansion of Eurasian languages ancestral to the historically attested ones. Beyond this migrationist view there were obviously dozens of thorough theories concerning potential linguistic expansions associated with specific prehistoric cultures, and a myriad of less developed alternatives, all of which deserved to be evaluated after the null hypothesis had been rejected.

Despite the shortcomings of the 2015 papers and their lack of testing or discussion of different language expansion models, the spread of the so-called “Yamnaya ancestry” – an admixture especially prevalent (after the demise of the Yamnaya) among the most likely ancient Uralic-speaking groups as well as among modern Uralic speakers and recently acculturated groups from Eastern Europe – has been nevertheless invariably concluded by each lab to support the theories of their leading archaeologist, often combined with pre-aDNA theories of geneticists based on modern haplogroup distributions. This is as evident a case of confirmation bias, circular reasoning, and jumping to conclusions as it gets.

Why many researchers of other labs have chosen to follow such conclusions instead of challenging or simply ignoring them is difficult to understand.

Related

Corded Ware and Bell Beaker related groups defined by patrilocality and female exogamy

tumulus-culture-eba-danube

Two new interesting papers concerning Corded Ware and Bell Beaker peoples appeared last week, supporting yet again what is already well-known since 2015 about West Uralic and North-West Indo-European speakers and their expansion.

Below are relevant excerpts (emphasis mine) and comments.

#UPDATE (27 OCT 2019): I have updated Y-DNA and mtDNA maps of Corded Ware, Bell Beaker, EBA, MBA, and LBA migrations. I have also updated PCA plots, which now include the newly reported samples and those from the Tollense valley, and I have tried some qpAdm models (see below).

I. Corded Ware and Battle Axe cultures

Open access The genomic ancestry of the Scandinavian Battle Axe Culture people and their relation to the broader Corded Ware horizon, by Malmström, Günther, et al. Philos. Trans. R. Soc. (2019).

I.1. Origins of Corded Ware peoples

The discovery of the Alexandria outlier represented a clear support for a long-lasting genomic difference between the two distinct cultural groups, Yamnaya and Corded Ware, already visible in an opposition Khvalynsk vs. late Sredni Stog ca. 4000 BC, i.e. well before the formation of both Late Eneolithic/Early Bronze Age groups.

However, the realization that it may not have been an Eneolithic individual, but rather a (Middle?) Bronze Age one, suggests that Sredni Stog was possibly not directly related to Corded Ware, and a potential direct connection with Yamnaya might have to be reevaluated, e.g. through the Carpathian Basin, as Anthony (2017) proposed.

pca-yamnaya-corded-ware-oblaczkowo
Principal component analysis of modern Europeans (grey) and projected ancient Europeans.

This new paper shows two early Corded Ware individuals from Obłaczkowo, Poland (ca. 2900-2600 BC) – hence close to the supposed original Proto-Corded Ware community – with an apparently (almost) full “Steppe-like” ancestry, clustering (almost) with Yamnaya individuals:

Similar to the BAC individuals, the newly sequenced individuals from the present-day Karlova in Estonia and Obłaczkowo in Poland appear to have strong genetic affinities to other individuals from BAC and CWC contexts across the Baltic Sea region. Some individuals from CWC contexts, including the two from Obłaczkowo, cluster closely with the potential source population of steppe-related ancestry, the Yamnaya herders. Notably, these individuals appear to be those with the earliest radiocarbon dates among all genetically investigated individuals from CWC contexts. Overall, for CWC-associated individuals, there is a clear trend of decreasing affinity to Yamnaya herders with time.

NOTE. Interestingly, this sample is almost certainly attributed to the skeleton E8-A, which had been supposedly already investigated by the Copenhagen group as the RISE1 sample:

We note that RISE1 is also described as the individual from Obłaczkowo feature E8-A. However, their genetic results differ from ours. They present this individual as a molecularly determined male that belongs to Y-chromosomal haplogroup (hg) R1b and to mtDNA hg K1b1a1 while our results show this individual to be female, carrying a mtDNA hg U3a’c profile

Since the typical Steppe_MLBA ancestry of Corded Ware groups does not show good fits for (Pre-)Yamnaya-derived ancestry, it is almost certain that these individuals will show no (or almost no) direct Yamnaya-related contribution, but rather a contribution of East European sub-Neolithic groups, more or less close to the steppe-forest region.

NOTE. They might show contributions from Pre-Yamnaya-influenced Sredni Stog, though, but if they show a contribution of Yamnaya, then they are probably outliers, related to Yamnaya vanguard groups (see image below). And for them to show it, then both sources, Yamnaya and Corded Ware, should be clearly distinguishable from each other and their relative contribution quantifiable in formal stats, something difficult (if not impossible) to ascertain today.

trypillian-yamnaya-influence-baltic
Trypillian routes of influence and Yamnaya culture influences in Central and Central-East Europe during the Late Eneolithic / Early Bronze Age. Images by Klochko (2009).

Their position in the published PCA – a plot apparently affected by projection bias – suggests a cluster in common with early Baltic samples, which are known to show contributions from East European sub-Neolithic populations (see qpAdm values for Baltic CWC samples).

NOTE. Results for previous samples labelled as Poland CWC are unreliable due to their low coverage.

The most interesting aspect about the ancestry shown by these early samples is their further support for an origin of the culture different than Sredni Stog, and for a rejection of the Alexandria outlier as ancestral to them, hence for a Volhynian-Podolian homeland of Proto-Corded Ware peoples, with an ancestry probably more closely related to the late Maykop Steppe- and Trypillian/GAC groups admixed with sub-Neolithic populations of the Eastern European Late Eneolithic.

NOTE. That is, unless there is a reason for the apparent increase in so-called “Steppe-ancestry” during the northward and westward migration of CWC peoples that represents another thing entirely…

#UPDATE (27 OCT 2019): Apparently, the PCA was actually not affected by projection bias:

Sample poz44 clusters ‘to the south’, with other early German ones, but also close to Yamnaya. Its poor coverage makes qpAdm results unreliable, but its common cluster close to central European and eastern CWC groups – despite belonging to the same Obłaczkowo site – supports that it is more representative of the Proto-CWC population than poz81.

Sample poz81 clusters with Yamnaya samples – or at least with the wider, Steppe-related cluster. Nevertheless, analyses with qpAdm – in combination with values obtained for other early Baltic samples – support that the ancestry of poz81 is more closely related to a core Corded Ware population admixed with sub-Neolithic peoples (similar to Samara LN).

NOTE. I have selected Czech CWC as a potential source closer to the Proto-CWC population, similar to models with Baltic samples. Since Czech CWC samples are later than these from Obłaczkowo, I have also checked the reverse model, with Poz81 and GAC Poland as a source for Czech CWC, and the fits are slightly worse. Anyway, ‘better’ or ‘worse’ p-values can’t determine the direction of migration

pca-corded-ware-poland-oblaczkowo-baltic-yamnaya
Detail of the PCA of Eurasian samples, including Corded Ware groups and related clusters, as well as outliers. Also marked is poz81.

I.2. CWC expansion under R1a bottlenecks

The two males in our dataset (ber1 and poz81) belonged to Y-chromosome R1a haplogroups, as do the majority of males (16/24) from the previously published CWC contexts, while a smaller fraction belonged to R1b [3/24] or I2a [3/24] lineages. The R1a haplogroup has not been found among Neolithic farmer populations nor in hunter–gatherer groups in central and western Europe, but it has been reported from eastern European hunter–gatherers and Eneolithic groups. Individuals from the Pontic–Caspian steppe, associated with the Yamnaya Culture, carry mostly R1b and not R1a haplotypes.

Sample poz81 is of basal hg. R1a-CTS4385*, an R1a-M417 subclade, supporting once again that most Corded Ware individuals from western and central European groups expanded under R1a-M417 (xZ645) lineages. The Battle Axe sample from Bergsgraven (ca. 2620-2470 BC) shows a basal hg. R1a-Y2395*, a R1a-Z283 subclade leading to the typically Fennoscandian R1a-Z284.

Both findings further support that typical lineages of West CWC groups, including R1a-M417 (xZ645) subclades, were fully replaced by incoming East Bell Beakers, and that the limited expansion of R1a-Z284 and I1 (the latter found in one newly reported Late Neolithic sample from Sweden) was the outcome of later regional bottlenecks within Scandinavia, after the creation of a maritime dominion by the Bell Beaker elites during the Dagger Period.

I.3. CWC and lactase persistence

(…) one of these individuals (kar1) carried at least one allele (-13910 C->T) associated with lactose tolerance, while the other two individuals (ber1 and poz81) carried at least one ancestral variant each, consistent with previous observations of low levels of lactose tolerance variants in the Neolithic and a slight increase among individuals from CWC contexts.

The fact that two early CWC individuals carry ancestral variants could be said to support the improbability of the individual from Alexandria representing a community ancestral to the Corded Ware community. On the other hand, the late CWC individual from Estonia carries one allele, but it still seems that only Bell Beakers and Steppe-related groups show the necessary two alleles during the Early Bronze Age, which is in line with a late Repin/early Yamnaya-related origin of the successful selection of the trait, consistent with the expansion of their specialized semi-nomadic cattle-breeding economy through the steppe biome during the Late Eneolithic.

rs4988235-lactase-persistence-history
Maps part of the public data used for the post by Iain Mathieson on Lactase Persistence. “By 2500 BP, the allele is present over a band stretching from Ireland to Central Asia at around 50 degrees latitude. This probably reflects the spread of Steppe ancestry populations in which the allele originated. However, the allele is still rare (say less than 1% frequency) over this entire range. It does not become common anywhere until some time in the past 2500 years – when it reaches its present-day high frequency in Britain and Central Europe”.

I.4. West Uralic spread from the East

The BAC groups fit as a sister group to the CWC-associated group from Estonia but not as a sister group to the CWC groups from Poland or Lithuania (|Z| > 3), indicating some differences in ancestry between these CWC groups and BAC. Supervised admixture modelling suggests that BAC may be the CWC-related group with the lowest YAM-related ancestry and with more ancestry from European Neolithic groups.

While the results of the paper are compatible with a migration from either the Eastern or the Western Baltic into Scandinavia, phylogeography and archaeology support that Battle Axe peoples emerged as a Baltic Corded Ware group close to the Vistula that expanded first to the north-east, and then to the west from Finland, continuing mostly unscathed during the whole Bronze Age mostly in eastern Fennoscandia with the development of Balto-Finnic- and Samic-speaking communities.

corded-ware-culture-ancestry-over-time
Correlation between f4(Chimp, LBK, YAM, X), where X is a CWC or BAC individual, and the date (BCE) of each individual. This statistic measures shared drift between CWC and Linear Pottery Culture (LBK) as opposed to YAM and should increase with the higher proportion of Neolithic farmer ancestry in CWC and BAC.

Radiocarbon dating showed that the three individuals from the Öllsjö megalithic tomb derived from later burials, where oll007 (2860–2500 cal BCE) overlaps with the time interval of the BAC, and oll009 and oll010 (1930–1650 cal BCE) fall within the Scandinavian Late Neolithic and Early Bronze Age

For more on how the Pitted Ware culture may have influenced Uralic-speaking Battle Axe peoples earlier than Indo-European-speaking Bell Beakers in Scandinavia, read more about Early Bronze Age Scandinavia and about the emergence of the Pre-Proto-Germanic community.

II. Bell Beakers through the Bronze Age

New paper (behind paywall) Kinship-based social inequality in Bronze Age Europe, by Mittnik et al. Science (2019).

II.1. Yamnaya vanguard settlers

In my last post, I showed how the ancestry of Corded Ware from Esperstedt is consistent with influence by incoming Yamnaya vanguard settlers or early Bell Beakers, stemming ultimately from the Carpathian Basin, something that could be inferred from the position of the Esperstedt outlier in the PCA, and by the knowledge of Yamnaya archaeological influences up to Saxony-Anhalt.

Yamnaya settlers are strongly suspected to have migrated in small so-called vanguard groups to the west and north of the Carpathians in the first half of the 3rd millennium BC, well before the eventual adoption of the Proto-Beaker package and their expansion ca. 2500 BC as East Bell Beakers.

Tauber Valley infiltration

As I mentioned in the books, one of the known – among the many more unknown – sites displaying Yamnaya-related traits and suggesting the expansion of Yamnaya settlers into Central Europe is Lauda-Königshofen, in the Tauber Valley.

From Diet and Mobility in the Corded Ware of Central Europe, by Sjögren, Price, & Kristiansen PLoS One (2017):

A series of CW cemeteries have been excavated in the Tauber valley. There are three large cemeteries known and some 30 smaller sites. The larger ones are Tauberbischofsheim-Dittingheim with 62 individuals, Tauberbischofsheim-Impfingen with 40 individuals, and Lauda-Königshofen with 91 individuals. The cemeteries are dispersed rather regularly along the Tauber valley, on both sides of the river, suggesting a quite densely settled landscape.

The Lauda-Königshofen graves consisted mostly of single inhumations in contracted position, usually oriented E-W or NE-SW. A total of 91 individuals were buried in 69 graves. At least 9 double graves and three graves with 3–4 individuals were present. In contrast to the common CW pattern, sexes were not distinguished by body position, only by grave goods. This trait is common in the Tauber valley and suggests a local burial tradition in this area. Stone axes were restricted to males, pottery to females, while other artifacts were common to both sexes. About a third of the graves were surrounded by ring ditches, suggesting palisade enclosures and possibly over-plowed barrows.

In particular, Frînculeasa, Preda, & Heyd (2015) used Lauda-Königshofen as representative of the mobility of horse-riding Yamnaya nomadic herders migrating into southern Germany, referring to the findings in Trautmann (2012) about the nomadic herders from the Tauber Valley, and their already known differences with other Corded Ware groups.

The likely influence of Yamnaya in the region has been reported at least since the 2000s, repeatedly mentioned by Jozef Bátora (2002, 2003, 2006), who compiled Yamnaya influences in a map that has been copied ever since, with little improvement over time. Heyd believes that there are potentially many Yamnaya remains along the Middle and Lower Danube and tributaries not yet found, though.

NOTE. Looking for this specific site, I realized that Bátora (and possibly many after him who, like me, copied his map) located Lauda-Königshofen in a more south-western position within Baden-Württemberg than its actual location. I have now corrected it in the maps of Chalcolithic migrations.

yamnaya-corded-ware-europe
Yamnaya influences in Central Europe suggestive of vanguard settlements, contemporary with Corded Ware groups. See full map.

Althäuser Hockergrab…Bell Beakers

Unfortunately, though, it is very difficult to attribute the reported R1b-L51 sample from the Tauber valley to a population preceding the arrival of East Bell Beakers in the region, so there is no uncontroversial smoking gun of Yamnaya vanguard settlers – yet. Reasons to doubt a Pre-Beaker origin are as follows:

1. This family of the Tauber valley shows a late radiocarbon date (ca. 2500 BC), i.e. from a time where East Bell Beakers are known to have been already expanding in all directions from the Middle and Upper Danube and its tributaries.

tauber-valley-althauser-hockergrab
Crouched burial from Althausen (Althäuser Hockergrab), dated ca. 2500 BC.

2. Archaeological information is scarce. Remains of these four individuals were discovered in 1939 and officially reported together with other findings in 1950, without any meaningful data that could distinguish between Bell Beakers and Corded Ware individuals.

This site is located in the Tauber valley, ca. 100 km to the northwest of the Lech valley. The site was discovered during the construction of a sports field in 1939 and was subsequently excavated by G. Müller and O. Paret. Four individuals in crouched position were found in the burial pit of a flat grave. The burial did not contain any grave goods, but due to the type of grave and positioning of the bodies (with heads pointing towards southwest) the site was attributed to the Corded Ware complex.

The classification of this burial as of CWC and not BBC seems to have been based entirely on the numerous CWC findings in the Tauber valley, rather than on its particular burial orientation following a regional custom (foreign to the described standard of both cultures), and on its grave type that was also found among Bell Beaker groups. Like many human remains recovered in dubious circumstances in the 20th century, these samples should have probably been labelled (at least in the genetic paper) more properly as Tauber_LN or Tauber_EBA.

yamnaya-bias-tauber-lech-valley
Changes in ancestry over time. (A) Median ages of individuals plotted against z scores of f4 (Mbuti, Test; Yamnaya_Samara, Anatolia_Neolithic) show increase of Anatolian farmer-related ancestry (indicated by more positive z-scores) and decrease of variation in ancestry over time. Grey shading indicates significant z scores, red line shonw near correlation (r = -0.35971; P = 0.003) and dotted lines the 95% confidence interval. (B) ancestry proportions on autosomes calculated with qpAdm. (C) Sex-bias z scores between autosomes and X chromosomes show significant male bias for steppe-related ancestry in the Tauber samples. Image modified from the paper: Surrounded with a blue circle in (A) are females with more Steppe-related ancestry, and in (C) surrounded by squares are the distinct sex biases found in the earliest BBC from the Tauber valley vs. later groups from the Lech valley.

3. In terms of ancestry, there seem to be no gross differences between the Lech Valley BBC individuals and previously reported South German Beakers, originally Yamnaya-like settlers admixing through exogamy with locals, including Corded Ware peoples, as the sex bias of the Lech Valley Beakers proves (see PCA plot below). In other words, northern and eastern Beakers admixed with regional (Epi-)Corded Ware females during their respective expansions, similar to how southern and western Beakers admixed with regional EEF-related females.

The two available Tauber Valley samples (“Tauber_CWC”) show the same pattern: a quite recent Steppe-related male bias and Anatolia_Neolithic-related female bias. Nevertheless, the male sample clusters ‘to the south’ in the PCA relative to all sampled Corded Ware individuals (see PCA plot below), and shows less Yamnaya-like ancestry than what is reported (or can be inferred) for Yamnaya from Hungary or early Bell Beakers of elevated Steppe-related ancestry.

yamnaya-ancestry-tauber-cwc-bbc-lech-eba-mba
Table S9. Three-way qpAdm admixture model for European MN/Chalcolithic group+Yamnaya_Samara. P-values greater than 0.05 (model is not rejected) marked in green.

The ancestry and position of the Althäuser male in the PCA is thus fully compatible with recently incoming East Bell Beakers admixing with local peoples (including Corded Ware) through exogamy, but not so much with a sample that would be expected from Yamanaya vanguard + Corded Ware-related ancestry (more like the Esperstedt outlier or the early France Beaker). Compared to the more ‘northern’ (fully Corded Ware-like) position ancestry of his female counterpart, there is little to support that both are part of the same native Tauber valley community after generations of ancestry levelling…

#UPDATE (27 OCT 2019): The PCA shows that the Althäuser male clusters, in fact, ‘to the north’ of the female one, almost on the same spot as a Bell Beaker sample from the Lech Valley.

Despite their reported damage and poor coverage, there seems to be a trend for qpAdm values to prefer a source population for the male (Alt_4) close to Germany Beakers, whereas the female sample (Alt_3) shows ‘better’ fits when a Corded Ware source is selected.

Also relevant is the Corded Ware ancestry of the male – closer to a Czech rather than German CWC source – compatible with an eastern origin, hence supporting a recent arrival via the Danube, in contrast to the local source of the CWC admixture of the female. The poorer coverage of the female sample makes these results questionable, though.

pca-bell-beaker-tauber-lech-valley-yamnaya-cwc
Detail of the PCA of Eurasian samples, including Bell Beaker groups and related clusters, as well as outliers. Also marked are the Tauber Valley male (M) and female (F).

4. The haplogroup inference is also unrevealing: whereas the paper reports that it is R1b-P310* (xU106, xP312), there is no data to support a xP312 call, so it may well be even within the P312 branch, like most sampled Bell Beaker males. Similarly, the paper also reports that HUGO_180Sk1 (ca. 2340 BC) shows a positive SNP for the U106 trunk, which would make it the earliest known U106 sample and originally from Central Europe, but there is no clear support for this SNP call, either. At least not in their downloadable BAM files, as far as I can tell. Even if both were true, they would merely confirm the path of expansion of Yamnaya / East Bell Beakers through the Danube, already visible in confirmed genomic data:

r1b-l51-archaic-yamnaya-bell-beakers
Distribution of ‘archaic’ R1b-L51 subclades in ancient samples, overlaid over a map of Yamnaya and Bell Beaker migrations. In blue, Yamnaya Pre-L51 from Lopatino (not shown) and R1b-L52* from BBC Augsburg. In violet, R1b-L51 (xP312,xU106) from BBC Prague and Poland. In maroon, hg. R1b-L151* from BBC Hungary, BA Bohemia, and (not shown) a potential sample from the Tauber Valley and one from BBC at Mondelange, which is certainly xU106, maybe xP312. Interestingly, the earliest sample of hg. R1b-U106 (a lineage more proper of northern Europe) has been found in a Bell Beaker from Radovesice (ca. 2350 BC), between two of these ‘archaic’ R1b-L51 samples; and a sample possibly of hg. R1b-ZZ11+ (ancestral to DF27 and U152) was found in a Bell Beaker from Quedlinburg, Germany (ca. 2290 BC), to the north-west of Bohemia. The oldest R1b-U152 are logically from Central Europe, too.

II.2. Proto-Celts and the Tumulus culture

The most interesting data from Mittnik et al. (2019) – overshadowed by the (at first sight) striking “CWC” label of the Althäuser male – is the finding that the most likely (Pre-)Proto-Celtic community of Southern Germany shows, as expected, major genetic continuity over time with Yamnaya/East Bell Beaker-derived patrilineal families, which suggests an almost full replacement of other Y-chromosome haplogroups in Southern German Bronze Age communities, too.

Sampled families form part of an evolving Bell Beaker-derived European BA cluster in common with other Indo-European-speaking cultures from Western, Southern, and Northern Europe, also including early Balto-Slavs, clearly distinct from the Corded Ware-related clusters surviving in the Eastern Baltic and the forest zone.

This Central European Bronze Age continuity is particularly visible in many generations of different patrilocal families practising female exogamy, showing patrilineal inheritance mainly under R1b-P312 (mostly U152+) lineages proper of Central European bottlenecks, all of them apparently following a similar sociopolitical system spanning roughly a thousand years, since the arrival of East Bell Beakers in the region (ca. 2500 BC) until – at least – the end of the Middle Bronze Age (ca. 1300 BC):

Here, we show a different kind of social inequality in prehistory, i.e., complex households that consisted of i) a higher-status core family, passing on wealth and status to descendants, ii) unrelated, wealthy and high-status non-local women and iii) local, low-status individuals. Based on comparisons of grave goods, several of the high-status non-local females could have come from areas inhabited by the Unetice culture, i.e., from a distance of at least 350 km. As the EBA evidence from most of Southern Germany is very similar to the Lech valley, we suggest that social structures comparable to our microregion existed in a much broader area. The EBA households in the Lech valley, however, seem similar to the later historically known oikos, the household sphere of classic Greece, as well as the Roman familia, both comprising the kin-related family and their slaves.

pca-lech-valley-bell-beaker-eba
Genetic structure of Late Neolithic and Bronze Age individuals from southern Germany. (A) Ancient individuals (covered at 20,000 or more SNPs) projected onto principal components defined by 1129 present day west Eurasians (shown in fig. S6); individuals in this study shown with outlines corresponding to their 87Sr/86Sr isotope value (black: consistent with local values, orange: uncertain/intermediate, red: inconsistent with local values). Selected published ancient European individuals are shown without outlines. Image modified from the paper. Surrounded by triangles in cyan, Corded Ware-like females; with a blue triangle, Yamnaya/Early BBC-like sample from the Tauber valley.

NOTE. For those unfamiliar with the usual clusters formed by the different populations in the PCA, you can check similar graphics: PCA with Bell Beaker communities, PCA with Yamnaya settlers from the Carpathians, a similar one from Wang et al. (2019) showing the Yamnaya-Hungary cline, or the chronological PCAs prepared by me for the books.

The gradual increase in local EEF-like ancestry among South Germany EBA and MBA communities over the previous BBC period offers a reasonable explanation as to how Italic and Celtic communities remained in loose contact (enough to share certain innovations) despite their physical separation by the Alps during the Early Bronze Age, and probably why sampled Bell Beakers from France were found to be the closest source of Celts arriving in Iberia during the Urnfield period.

Furthermore, continued contacts with Únětice-related peoples through exogamy also show how Celtic-speaking communities closer to the Danube might have influenced (and might have been influenced by) Germanic-speaking communities of the Nordic Late Neolithic and Bronze Age, helping explain their potentially long-lasting linguistic exchange.

Like other previous Neolithic or Chalcolithic groups that Yamnaya and Bell Beakers encountered in Europe, ancestry related to the Corded Ware culture became part of Bell Beaker groups during their expansion and later during the ancestry levelling in the European Early Bronze Age, which helps us distinguish the evolution of Indo-European-speaking communities in Europe, and suggests likely contacts between different cultural groups separated hundreds of km. from each other.

All in all, there is nothing to support that (epi-)Corded Ware groups might have survived in any way in Central or Western Europe: whether through their culture, their Y-chromosome haplogroups, or their ancestry, they followed the fate of other rapidly expanding groups before them, viz. Funnelbeaker, Baden, or Globular Amphorae cultural groups. This is very much unlike the West Uralic-speaking territory in the Eastern Baltic and the Russian forests, where Corded Ware-related cultures thrived during the Bronze Age.

lech-valley-yamnaya-ancestry-over-time
f4-statistics showing differences in ancestry in populations grouped by period. An increase in affinity to ancestry related to Anatolia Neolithic over time. Males and females grouped together shown as upward and downward pointing triangles, respectively.

Conclusion

It was about time that geneticists caught up with the relevance of Y-DNA bottlenecks when assessing migrations and cultural developments.

From Malmström et al. (2019):

The paternal lineages found in the BAC/CWC individuals remain enigmatic. The majority of individuals from CWC contexts that have been genetically investigated this far for the Y-chromosome belong to Y-haplogroup R1a, while the majority of sequenced individuals of the presumed source population of Yamnaya steppe herders belong to R1b. R1a has been found in Mesolithic and Neolithic Ukraine. This opens the possibility that the Yamnaya and CWC complexes may have been structured in terms of paternal lineages—possibly due to patrilineal inheritance systems in the societies — and that genetic studies have not yet targeted the direct sources of the expansions into central and northern Europe.

From Gibbons (2019), a commentary to Mittnik et al. (2019):

Some of the early farmers studied were part of the Neolithic Bell Beaker culture, named for the shape of their pots. Later generations of Bronze Age men who retained Bell Beaker DNA were high-ranking, buried with bronze and copper daggers, axes, and chisels. Those men carried a Y chromosome variant that is still common today in Europe. In contrast, low-ranking men without grave goods had different Y chromosomes, showing a different ancestry on their fathers’ side, and suggesting that men with Bell Beaker ancestry were richer and had more sons, whose genes persist to the present.

There was no sign of these women’s daughters in the burials, suggesting they, too, were sent away for marriage, in a pattern that persisted for 700 years. The only local women were girls from high-status families who died before ages 15 to 17, and poor, unrelated women without grave goods, probably servants, Mittnik says. Strontium levels from three men, in contrast, showed that although they had left the valley as teens, they returned as adults.

Also, from Scientific American:

(…) it has long been assumed that prior to the Athenian and Roman empires,—which arose nearly 2,500 and more than 2,000 years ago, respectively—human social structure was relatively straightforward: you had those who were in power and those who were not. A study published Thursday in Science suggests it was not that simple. As far back as 4,000 years ago, at the beginning of the Bronze Age and long before Julius Caesar presided over the Forum, human families of varying status levels had quite intimate relationships. Elites lived together with those of lower social classes and women who migrated in from outside communities. It appears early human societies operated in a complex, class-based system that propagated through generations.

It seems wrong (to me, at least) that the author and – as he believes – archaeologists and historians had “assumed” a different social system for the European Bronze Age, which means they hadn’t read about how Indo-European societies were structured. For example, long ago Benveniste (1969) already drew some coherent picture of these prehistoric peoples based on their reconstructed language alone: regarding their patrilocal and patrilineal family system; regarding their customs of female exogamy and marriage system; and regarding the status of foreigners and slaves as movable property in their society.

A long-lasting and pervasive social system of Bronze Age elites under Yamnaya lineages strikingly similar to this Southern German region can be easily assumed for the British Isles and Iberia, and it is likely to be also found in the Low Countries, Northern Germany, Denmark, Italy, France, Bohemia and Moravia, etc., but also (with some nuances) in Southern Scandinavia and Central-East Europe during the Bronze Age.

Therefore, only the modern genetic pool of some border North-West Indo-European-speaking communities of Europe need further information to describe a precise chain of events before their eventual expansion in more recent times:

  1. the relative geographical isolation causing the visible regional founder effects in Scandinavia, proper of the maritime dominion of the Nordic Late Neolithic (related thus to the Island Biogeography Theory); and
  2. the situation of the (Pre-)Proto-Balto-Slavic community close to the Western Baltic which, I imagine, will be shown to be related to a resurge of local lineages, possibly due to a shift of power structures similar to the case described for Babia Góra.

NOTE. Rumour has it that R1b-L23 lineages have already been found among Mycenaeans, while they haven’t been found among sampled early West European Corded Ware groups, so the westward expansion of Indo-European-speaking Yamnaya-derived peoples mainly with R1b-L23 lineages through the Danube Basin merely lacks official confirmation.

Related

Yamnaya ancestry: mapping the Proto-Indo-European expansions

steppe-ancestry-expansion-europe

The latest papers from Ning et al. Cell (2019) and Anthony JIES (2019) have offered some interesting new data, supporting once more what could be inferred since 2015, and what was evident in population genomics since 2017: that Proto-Indo-Europeans expanded under R1b bottlenecks, and that the so-called “Steppe ancestry” referred to two different components, one – Yamnaya or Steppe_EMBA ancestry – expanding with Proto-Indo-Europeans, and the other one – Corded Ware or Steppe_MLBA ancestry – expanding with Uralic speakers.

The following maps are based on formal stats published in the papers and supplementary materials from 2015 until today, mainly on Wang et al. (2018 & 2019), Mathieson et al. (2018) and Olalde et al. (2018), and others like Lazaridis et al. (2016), Lazaridis et al. (2017), Mittnik et al. (2018), Lamnidis et al. (2018), Fernandes et al. (2018), Jeong et al. (2019), Olalde et al. (2019), etc.

NOTE. As in the Corded Ware ancestry maps, the selected reports in this case are centered on the prototypical Yamnaya ancestry vs. other simplified components, so everything else refers to simplistic ancestral components widespread across populations that do not necessarily share any recent connection, much less a language. In fact, most of the time they clearly didn’t. They can be interpreted as “EHG that is not part of the Yamnaya component”, or “CHG that is not part of the Yamnaya component”. They can’t be read as “expanding EHG people/language” or “expanding CHG people/language”, at least no more than maps of “Steppe ancestry” can be read as “expanding Steppe people/language”. Also, remember that I have left the default behaviour for color classification, so that the highest value (i.e. 1, or white colour) could mean anything from 10% to 100% depending on the specific ancestry and period; that’s what the legend is for… But, fere libenter homines id quod volunt credunt.

Sections:

  1. Neolithic or the formation of Early Indo-European
  2. Eneolithic or the expansion of Middle Proto-Indo-European
  3. Chalcolithic / Early Bronze Age or the expansion of Late Proto-Indo-European
  4. European Early Bronze Age and MLBA or the expansion of Late PIE dialects

1. Neolithic

Anthony (2019) agrees with the most likely explanation of the CHG component found in Yamnaya, as derived from steppe hunter-fishers close to the lower Volga basin. The ultimate origin of this specific CHG-like component that eventually formed part of the Pre-Yamnaya ancestry is not clear, though:

The hunter-fisher camps that first appeared on the lower Volga around 6200 BC could represent the migration northward of un-admixed CHG hunter-fishers from the steppe parts of the southeastern Caucasus, a speculation that awaits confirmation from aDNA.

neolithic-chg-ancestry
Natural neighbor interpolation of CHG ancestry among Neolithic populations. See full map.

The typical EHG component that formed part eventually of Pre-Yamnaya ancestry came from the Middle Volga Basin, most likely close to the Samara region, as shown by the sampled Samara hunter-gatherer (ca. 5600-5500 BC):

After 5000 BC domesticated animals appeared in these same sites in the lower Volga, and in new ones, and in grave sacrifices at Khvalynsk and Ekaterinovka. CHG genes and domesticated animals flowed north up the Volga, and EHG genes flowed south into the North Caucasus steppes, and the two components became admixed.

neolithic-ehg-ancestry
Natural neighbor interpolation of EHG ancestry among Neolithic populations. See full map.

To the west, in the Dnieper-Dniester area, WHG became the dominant ancestry after the Mesolithic, at the expense of EHG, revealing a likely mating network reaching to the north into the Baltic:

Like the Mesolithic and Neolithic populations here, the Eneolithic populations of Dnieper-Donets II type seem to have limited their mating network to the rich, strategic region they occupied, centered on the Rapids. The absence of CHG shows that they did not mate frequently if at all with the people of the Volga steppes (…)

neolithic-whg-ancestry
Natural neighbor interpolation of WHG ancestry among Neolithic populations. See full map.

North-West Anatolia Neolithic ancestry, proper of expanding Early European farmers, is found up to border of the Dniester, as Anthony (2007) had predicted.

neolithic-anatolia-farmer-ancestry
Natural neighbor interpolation of Anatolia Neolithic ancestry among Neolithic populations. See full map.

2. Eneolithic

From Anthony (2019):

After approximately 4500 BC the Khvalynsk archaeological culture united the lower and middle Volga archaeological sites into one variable archaeological culture that kept domesticated sheep, goats, and cattle (and possibly horses). In my estimation, Khvalynsk might represent the oldest phase of PIE.

(…) this middle Volga mating network extended down to the North Caucasian steppes, where at cemeteries such as Progress-2 and Vonyuchka, dated 4300 BC, the same Khvalynsk-type ancestry appeared, an admixture of CHG and EHG with no Anatolian Farmer ancestry, with steppe-derived Y-chromosome haplogroup R1b. These three individuals in the North Caucasus steppes had higher proportions of CHG, overlapping Yamnaya. Without any doubt, a CHG population that was not admixed with Anatolian Farmers mated with EHG populations in the Volga steppes and in the North Caucasus steppes before 4500 BC. We can refer to this admixture as pre-Yamnaya, because it makes the best currently known genetic ancestor for EHG/CHG R1b Yamnaya genomes.

From Wang et al (2019):

Three individuals from the sites of Progress 2 and Vonyuchka 1 in the North Caucasus piedmont steppe (‘Eneolithic steppe’), which harbour EHG and CHG related ancestry, are genetically very similar to Eneolithic individuals from Khvalynsk II and the Samara region. This extends the cline of dilution of EHG ancestry via CHG-related ancestry to sites immediately north of the Caucasus foothills

eneolithic-pre-yamnaya-ancestry
Natural neighbor interpolation of Pre-Yamnaya ancestry among Neolithic populations. See full map. This map corresponds roughly to the map of Khvalynsk-Novodanilovka expansion, and in particular to the expansion of horse-head pommel-scepters (read more about Khvalynsk, and specifically about horse symbolism)

NOTE. Unpublished samples from Ekaterinovka have been previously reported as within the R1b-L23 tree. Interestingly, although the Varna outlier is a female, the Balkan outlier from Smyadovo shows two positive SNP calls for hg. R1b-M269. However, its poor coverage makes its most conservative haplogroup prediction R-M343.

The formation of this Pre-Yamnaya ancestry sets this Volga-Caucasus Khvalynsk community apart from the rest of the EHG-like population of eastern Europe.

eneolithic-ehg-ancestry
Natural neighbor interpolation of non-Pre-Yamnaya EHG ancestry among Eneolithic populations. See full map.

Anthony (2019) seems to rely on ADMIXTURE graphics when he writes that the late Sredni Stog sample from Alexandria shows “80% Khvalynsk-type steppe ancestry (CHG&EHG)”. While this seems the most logical conclusion of what might have happened after the Suvorovo-Novodanilovka expansion through the North Pontic steppes (see my post on “Steppe ancestry” step by step), formal stats have not confirmed that.

In fact, analyses published in Wang et al. (2019) rejected that Corded Ware groups are derived from this Pre-Yamnaya ancestry, a reality that had been already hinted in Narasimhan et al. (2018), when Steppe_EMBA showed a poor fit for expanding Srubna-Andronovo populations. Hence the need to consider the whole CHG component of the North Pontic area separately:

eneolithic-chg-ancestry
Natural neighbor interpolation of non-Pre-Yamnaya CHG ancestry among Eneolithic populations. See full map. You can read more about population movements in the late Sredni Stog and closer to the Proto-Corded Ware period.

NOTE. Fits for WHG + CHG + EHG in Neolithic and Eneolithic populations are taken in part from Mathieson et al. (2019) supplementary materials (download Excel here). Unfortunately, while data on the Ukraine_Eneolithic outlier from Alexandria abounds, I don’t have specific data on the so-called ‘outlier’ from Dereivka compared to the other two analyzed together, so these maps of CHG and EHG expansion are possibly showing a lesser distribution to the west than the real one ca. 4000-3500 BC.

eneolithic-whg-ancestry
Natural neighbor interpolation of WHG ancestry among Eneolithic populations. See full map.

Anatolia Neolithic ancestry clearly spread to the east into the north Pontic area through a Middle Eneolithic mating network, most likely opened after the Khvalynsk expansion:

eneolithic-anatolia-farmer-ancestry
Natural neighbor interpolation of Anatolia Neolithic ancestry among Eneolithic populations. See full map.
eneolithic-iran-chl-ancestry
Natural neighbor interpolation of Iran Chl. ancestry among Eneolithic populations. See full map.

Regarding Y-chromosome haplogroups, Anthony (2019) insists on the evident association of Khvalynsk, Yamnaya, and the spread of Pre-Yamnaya and Yamnaya ancestry with the expansion of elite R1b-L754 (and some I2a2) individuals:

eneolithic-early-y-dna
Y-DNA haplogroups in West Eurasia during the Early Eneolithic in the Pontic-Caspian steppes. See full map, and see culture, ADMIXTURE, Y-DNA, and mtDNA maps of the Early Eneolithic and Late Eneolithic.

3. Early Bronze Age

Data from Wang et al. (2019) show that Corded Ware-derived populations do not have good fits for Eneolithic_Steppe-like ancestry, no matter the model. In other words: Corded Ware populations show not only a higher contribution of Anatolia Neolithic ancestry (ca. 20-30% compared to the ca. 2-10% of Yamnaya); they show a different EHG + CHG combination compared to the Pre-Yamnaya one.

eneolithic-steppe-best-fits
Supplementary Table 13. P values of rank=2 and admixture proportions in modelling Steppe ancestry populations as a three-way admixture of Eneolithic steppe Anatolian_Neolithic and WHG using 14 outgroups.
Left populations: Test, Eneolithic_steppe, Anatolian_Neolithic, WHG.
Right populations: Mbuti.DG, Ust_Ishim.DG, Kostenki14, MA1, Han.DG, Papuan.DG, Onge.DG, Villabruna, Vestonice16, ElMiron, Ethiopia_4500BP.SG, Karitiana.DG, Natufian, Iran_Ganj_Dareh_Neolithic.

Yamnaya Kalmykia and Afanasievo show the closest fits to the Eneolithic population of the North Caucasian steppes, rejecting thus sizeable contributions from Anatolia Neolithic and/or WHG, as shown by the SD values. Both probably show then a Pre-Yamnaya ancestry closest to the late Repin population.

wang-eneolithic-steppe-caucasus-yamnaya
Modelling results for the Steppe and Caucasus cluster. Admixture proportions based on (temporally and geographically) distal and proximal models, showing additional AF ancestry in Steppe groups and additional gene flow from the south in some of the Steppe groups as well as the Caucasus groups. See tables above. Modified from Wang et al. (2019). Within a blue square, Yamnaya-related groups; within a cyan square, Corded Ware-related groups. Green background behind best p-values. In red circle, SD of AF/WHG ancestry contribution in Afanasevo and Yamnaya Kalmykia, with ranges that almost include 0%.

EBA maps include data from Wang et al. (2018) supplementary materials, specifically unpublished Yamnaya samples from Hungary that appeared in analysis of the preprint, but which were taken out of the definitive paper. Their location among Yamnaya settlers from Hungary is speculative, although most uncovered kurgans in Hungary are concentrated in the Tisza-Danube interfluve.

eba-yamnaya-ancestry
Natural neighbor interpolation of Pre-Yamnaya ancestry among Early Bronze Age populations. See full map. This map corresponds roughly with the known expansion of late Repin/Yamnaya settlers.

The Y-chromosome bottleneck of elite males from Proto-Indo-European clans under R1b-L754 and some I2a2 subclades, already visible in the Khvalynsk sampling, became even more noticeable in the subsequent expansion of late Repin/early Yamnaya elites under R1b-L23 and I2a-L699:

chalcolithic-early-y-dna
Y-DNA haplogroups in West Eurasia during the Yamnaya expansion. See full map and maps of cultures, ADMIXTURE, Y-DNA, and mtDNA of the Early Chalcolithic and Yamnaya Hungary.

Maps of CHG, EHG, Anatolia Neolithic, and probably WHG show the expansion of these components among Corded Ware-related groups in North Eurasia, apart from other cultures close to the Caucasus:

NOTE. For maps with actual formal stats of Corded Ware ancestry from the Early Bronze Age to the modern times, you can read the post Corded Ware ancestry in North Eurasia and the Uralic expansion.

eba-chg-ancestry
Natural neighbor interpolation of non-Pre-Yamnaya CHG ancestry among Early Bronze Age populations. See full map.
eba-ehg-ancestry
Natural neighbor interpolation of non-Pre-Yamnaya EHG ancestry among Early Bronze Age populations. See full map.
eba-whg-ancestry
Natural neighbor interpolation of WHG ancestry among Early Bronze Age populations. See full map.
eba-anatolia-farmer-ancestry
Natural neighbor interpolation of Anatolia Neolithic ancestry among Early Bronze Age populations. See full map.
eba-iran-chl-ancestry
Natural neighbor interpolation of Iran Chl. ancestry among Early Bronze Age populations. See full map.

4. Middle to Late Bronze Age

The following maps show the most likely distribution of Yamnaya ancestry during the Bell Beaker-, Balkan-, and Sintashta-Potapovka-related expansions.

4.1. Bell Beakers

The amount of Yamnaya ancestry is probably overestimated among populations where Bell Beakers replaced Corded Ware. A map of Yamnaya ancestry among Bell Beakers gets trickier for the following reasons:

  • Expanding Repin peoples of Pre-Yamnaya ancestry must have had admixture through exogamy with late Sredni Stog/Proto-Corded Ware peoples during their expansion into the North Pontic area, and Sredni Stog in turn had probably some Pre-Yamnaya admixture, too (although they don’t appear in the simplistic formal stats above). This is supported by the increase of Anatolia farmer ancestry in more western Yamna samples.
  • Later, Yamnaya admixed through exogamy with Corded Ware-like populations in Central Europe during their expansion. Even samples from the Middle to Upper Danube and around the Lower Rhine will probably show increasing contributions of Steppe_MLBA, at the same time as they show an increasing proportion of EEF-related ancestry.
  • To complicate things further, the late Corded Ware Espersted family (from ca. 2500 BC or later) shows, in turn, what seems like a recent admixture with Yamnaya vanguard groups, with the sample of highest Yamnaya ancestry being the paternal uncle of other individuals (all of hg. R1a-M417), suggesting that there might have been many similar Central European mating networks from the mid-3rd millennium BC on, of (mainly) Yamnaya-like R1b elites displaying a small proportion of CW-like ancestry admixing through exogamy with Corded Ware-like peoples who already had some Yamnaya ancestry.
mlba-yamnaya-ancestry
Natural neighbor interpolation of Yamnaya ancestry among Middle to Late Bronze Age populations (Esperstedt CWC site close to BK_DE, label is hidden by BK_DE_SAN). See full map. You can see how this map correlated with the map of Late Copper Age migrations and Yamanaya into Bell Beaker expansion.

NOTE. Terms like “exogamy”, “male-driven migration”, and “sex bias”, are not only based on the Y-chromosome bottlenecks visible in the different cultural expansions since the Palaeolithic. Despite the scarce sampling available in 2017 for analysis of “Steppe ancestry”-related populations, it appeared to show already a male sex bias in Goldberg et al. (2017), and it has been confirmed for Neolithic and Copper Age population movements in Mathieson et al. (2018) – see Supplementary Table 5. The analysis of male-biased expansion of “Steppe ancestry” in CWC Esperstedt and Bell Beaker Germany is, for the reasons stated above, not very useful to distinguish their mutual influence, though.

Based on data from Olalde et al. (2019), Bell Beakers from Germany are the closest sampled ones to expanding East Bell Beakers, and those close to the Rhine – i.e. French, Dutch, and British Beakers in particular – show a clear excess “Steppe ancestry” due to their exogamy with local Corded Ware groups:

Only one 2-way model fits the ancestry in Iberia_CA_Stp with P-value>0.05: Germany_Beaker + Iberia_CA. Finding a Bell Beaker-related group as a plausible source for the introduction of steppe ancestry into Iberia is consistent with the fact that some of the individuals in the Iberia_CA_Stp group were excavated in Bell Beaker associated contexts. Models with Iberia_CA and other Bell Beaker groups such as France_Beaker (P-value=7.31E-06), Netherlands_Beaker (P-value=1.03E-03) and England_Beaker (P-value=4.86E-02) failed, probably because they have slightly higher proportions of steppe ancestry than the true source population.

olalde-iberia-chalcolithic

The exogamy with Corded Ware-like groups in the Lower Rhine Basin seems at this point undeniable, as is the origin of Bell Beakers around the Middle-Upper Danube Basin from Yamnaya Hungary.

To avoid this excess “Steppe ancestry” showing up in the maps, since Bell Beakers from Germany pack the most Yamnaya ancestry among East Bell Beakers outside Hungary (ca. 51.1% “Steppe ancestry”), I equated this maximum with BK_Scotland_Ach (which shows ca. 61.1% “Steppe ancestry”, highest among western Beakers), and applied a simple rule of three for “Steppe ancestry” in Dutch and British Beakers.

NOTE. Formal stats for “Steppe ancestry” in Bell Beaker groups are available in Olalde et al. (2018) supplementary materials (PDF). I didn’t apply this adjustment to Bk_FR groups because of the R1b Bell Beaker sample from the Champagne/Alsace region reported by Samantha Brunel that will pack more Yamnaya ancestry than any other sampled Beaker to date, hence probably driving the Yamnaya ancestry up in French samples.

The most likely outcome in the following years, when Yamnaya and Corded Ware ancestry are investigated separately, is that Yamnaya ancestry will be much lower the farther away from the Middle and Lower Danube region, similar to the case in Iberia, so the map above probably overestimates this component in most Beakers to the north of the Danube. Even the late Hungarian Beaker samples, who pack the highest Yamnaya ancestry (up to 75%) among Beakers, represent likely a back-migration of Moravian Beakers, and will probably show a contribution of Corded Ware ancestry due to the exogamy with local Moravian groups.

Despite this decreasing admixture as Bell Beakers spread westward, the explosive expansion of Yamnaya R1b male lineages (in words of David Reich) and the radical replacement of local ones – whether derived from Corded Ware or Neolithic groups – shows the true extent of the North-West Indo-European expansion in Europe:

chalcolithic-late-y-dna
Y-DNA haplogroups in West Eurasia during the Bell Beaker expansion. See full map and see maps of cultures, ADMIXTURE, Y-DNA, and mtDNA of the Late Copper Age and of the Yamnaya-Bell Beaker transition.

4.2. Palaeo-Balkan

There is scarce data on Palaeo-Balkan movements yet, although it is known that:

  1. Yamnaya ancestry appears among Mycenaeans, with the Yamnaya Bulgaria sample being its best current ancestral fit;
  2. the emergence of steppe ancestry and R1b-M269 in the eastern Mediterranean was associated with Ancient Greeks;
  3. Thracians, Albanians, and Armenians also show R1b-M269 subclades and “Steppe ancestry”.

4.3. Sintashta-Potapovka-Filatovka

Interestingly, Potapovka is the only Corded Ware derived culture that shows good fits for Yamnaya ancestry, despite having replaced Poltavka in the region under the same Corded Ware-like (Abashevo) influence as Sintashta.

This proves that there was a period of admixture in the Pre-Proto-Indo-Iranian community between CWC-like Abashevo and Yamnaya-like Catacomb-Poltavka herders in the Sintashta-Potapovka-Filatovka community, probably more easily detectable in this group because of the specific temporal and geographic sampling available.

srubnaya-yamnaya-ehg-chg-ancestry
Supplementary Table 14. P values of rank=3 and admixture proportions in modelling Steppe ancestry populations as a four-way admixture of distal sources EHG, CHG, Anatolian_Neolithic and WHG using 14 outgroups.
Left populations: Steppe cluster, EHG, CHG, WHG, Anatolian_Neolithic
Right populations: Mbuti.DG, Ust_Ishim.DG, Kostenki14, MA1, Han.DG, Papuan.DG, Onge.DG, Villabruna, Vestonice16, ElMiron, Ethiopia_4500BP.SG, Karitiana.DG, Natufian, Iran_Ganj_Dareh_Neolithic.

Srubnaya ancestry shows a best fit with non-Pre-Yamnaya ancestry, i.e. with different CHG + EHG components – possibly because the more western Potapovka (ancestral to Proto-Srubnaya Pokrovka) also showed good fits for it. Srubnaya shows poor fits for Pre-Yamnaya ancestry probably because Corded Ware-like (Abashevo) genetic influence increased during its formation.

On the other hand, more eastern Corded Ware-derived groups like Sintashta and its more direct offshoot Andronovo show poor fits with this model, too, but their fits are still better than those including Pre-Yamnaya ancestry.

mlba-ehg-ancestry
Natural neighbor interpolation of non-Pre-Yamnaya EHG ancestry among Middle to Late Bronze Age populations. See full map.
mlba-chg-ancestry
Natural neighbor interpolation of non-Pre-Yamnaya CHG ancestry among Middle to Late Bronze Age populations. See full map.
mlba-anatolia-farmer-ancestry
Natural neighbor interpolation of Anatolia Neolithic ancestry among Middle to Late Bronze Age populations. See full map.
mlba-iran-chl-ancestry
Natural neighbor interpolation of Iran Chl. ancestry among Middle to Late Bronze Age populations. See full map.

NOTE For maps with actual formal stats of Corded Ware ancestry from the Early Bronze Age to the modern times, you should read the post Corded Ware ancestry in North Eurasia and the Uralic expansion instead.

The bottleneck of Proto-Indo-Iranians under R1a-Z93 was not yet complete by the time when the Sintashta-Potapovka-Filatovka community expanded with the Srubna-Andronovo horizon:

early-bronze-age-y-dna
Y-DNA haplogroups in West Eurasia during the European Early Bronze Age. See full map and see maps of cultures, ADMIXTURE, Y-DNA, and mtDNA of the Early Bronze Age.

4.4. Afanasevo

At the end of the Afanasevo culture, at least three samples show hg. Q1b (ca. 2900-2500 BC), which seemed to point to a resurgence of local lineages, despite continuity of the prototypical Pre-Yamnaya ancestry. On the other hand, Anthony (2019) makes this cryptic statement:

Yamnaya men were almost exclusively R1b, and pre-Yamnaya Eneolithic Volga-Caspian-Caucasus steppe men were principally R1b, with a significant Q1a minority.

Since the only available samples from the Khvalynsk community are R1b (x3), Q1a(x1), and R1a(x1), it seems strange that Anthony would talk about a “significant minority”, unless Q1a (potentially Q1b in the newer nomenclature) will pop up in some more individuals of those ca. 30 new to be published. Because he also mentions I2a2 as appearing in one elite burial, it seems Q1a (like R1a-M459) will not appear under elite kurgans, although it is still possible that hg. Q1a was involved in the expansion of Afanasevo to the east.

middle-bronze-age-y-dna
Y-DNA haplogroups in West Eurasia during the Middle Bronze Age. See full map and see maps of cultures, ADMIXTURE, Y-DNA, and mtDNA of the Middle Bronze Age and the Late Bronze Age.

Okunevo, which replaced Afanasevo in the Altai region, shows a majority of hg. Q1b, but also some R1b-M269 samples proper of Afanasevo, suggesting partial genetic continuity.

NOTE. Other sampled Siberian populations clearly show a variety of Q subclades that likely expanded during the Palaeolithic, such as Baikal EBA samples from Ust’Ida and Shamanka with a majority of Q1b, and hg. Q reported from Elunino, Sagsai, Khövsgöl, and also among peoples of the Srubna-Andronovo horizon (the Krasnoyarsk MLBA outlier), and in Karasuk.

From Damgaard et al. Science (2018):

(…) in contrast to the lack of identifiable admixture from Yamnaya and Afanasievo in the CentralSteppe_EMBA, there is an admixture signal of 10 to 20% Yamnaya and Afanasievo in the Okunevo_EMBA samples, consistent with evidence of western steppe influence. This signal is not seen on the X chromosome (qpAdm P value for admixture on X 0.33 compared to 0.02 for autosomes), suggesting a male-derived admixture, also consistent with the fact that 1 of 10 Okunevo_EMBA males carries a R1b1a2a2 Y chromosome related to those found in western pastoralists. In contrast, there is no evidence of western steppe admixture among the more eastern Baikal region region Bronze Age (~2200 to 1800 BCE) samples.

This Yamnaya ancestry has been also recently found to be the best fit for the Iron Age population of Shirenzigou in Xinjiang – where Tocharian languages were attested centuries later – despite the haplogroup diversity acquired during their evolution, likely through an intermediate Chemurchek culture (see a recent discussion on the elusive Proto-Tocharians).

Haplogroup diversity seems to be common in Iron Age populations all over Eurasia, most likely due to the spread of different types of sociopolitical structures where alliances played a more relevant role in the expansion of peoples. A well-known example of this is the spread of Akozino warrior-traders in the whole Baltic region under a partial N1a-VL29-bottleneck associated with the emerging chiefdom-based systems under the influence of expanding steppe nomads.

early-iron-age-y-dna
Y-DNA haplogroups in West Eurasia during the Early Iron Age. See full map and see maps of cultures, ADMIXTURE, Y-DNA, and mtDNA of the Early Iron Age and Late Iron Age.

Surprisingly, then, Proto-Tocharians from Shirenzigou pack up to 74% Yamnaya ancestry, in spite of the 2,000 years that separate them from the demise of the Afanasevo culture. They show more Yamnaya ancestry than any other population by that time, being thus a sort of Late PIE fossils not only in their archaic dialect, but also in their genetic profile:

shirenzigou-afanasievo-yamnaya-andronovo-srubna-ulchi-han

The recent intrusion of Corded Ware-like ancestry, as well as the variable admixture with Siberian and East Asian populations, both point to the known intense Old Iranian and Old/Middle Chinese contacts. The scarce Proto-Samoyedic and Proto-Turkic loans in Tocharian suggest a rather loose, probably more distant connection with East Uralic and Altaic peoples from the forest-steppe and steppe areas to the north (read more about external influences on Tocharian).

Interestingly, both R1b samples, MO12 and M15-2 – likely of Asian R1b-PH155 branch – show a best fit for Andronovo/Srubna + Hezhen/Ulchi ancestry, suggesting a likely connection with Iranians to the east of Xinjiang, who later expanded as the Wusun and Kangju. How they might have been related to Huns and Xiongnu individuals, who also show this haplogroup, is yet unknown, although Huns also show hg. R1a-Z93 (probably most R1a-Z2124) and Steppe_MLBA ancestry, earlier associated with expanding Iranian peoples of the Srubna-Andronovo horizon.

All in all, it seems that prehistoric movements explained through the lens of genetic research fit perfectly well the linguistic reconstruction of Proto-Indo-European and Proto-Uralic.

Related

Ancient Sardinia hints at Mesolithic spread of R1b-V88, and Western EEF-related expansion of Vasconic

nuragic-sardinia-neolithic

New preprint Population history from the Neolithic to present on the Mediterranean island of Sardinia: An ancient DNA perspective, by Marcus et al. bioRxiv (2019)

Interesting excerpts (emphasis mine, edited for clarity):

On the high frequency of R1b-V88

Our genome-wide data allowed us to assign Y haplogroups for 25 ancient Sardinian individuals. More than half of them consist of R1b-V88 (n=10) or I2-M223 (n=7).

Francalacci et al. (2013) identi fied three major Sardinia-specifi c founder clades based on present-day variation within the haplogroups I2-M26, G2-L91 and R1b-V88, and here we found each of those broader haplogroups in at least one ancient Sardinian individual. Two major present-day Sardinian haplogroups, R1b-M269 and E-M215, are absent.

Compared to other Neolithic and present-day European populations, the number of identi fied R1b-V88 carriers is relatively high.

(…)ancient Sardinian mtDNA haplotypes belong almost exclusively to macro-haplogroups HV (n = 16), JT (n = 17) and U (n = 9), a composition broadly similar to other European Neolithic populations.

r1b-v88-europe
Geographic and temporal distribution of R1b-V88 Y-haplotypes in ancient European samples. We plot the geographic position of all ancient samples inferred to carry R1b-V88 equivalent markers. Dates are given as years BCE (means of calibrated 2s radio-carbon dates). Multiple V88 individuals with similar geographic positions are vertically stacked. We additionally color-code the status of the R1b-V88 subclade R1b-V2197, which is found in most present-day African R1b-V88 carriers.

On the origin of a Vasconic-like Paleosardo with the Western EEF

(…) the Neolithic (and also later) ancient Sardinian individuals sit between early Neolithic Iberian and later Copper Age Iberian populations, roughly on an axis that differentiates WHG and EEF populations and embedded in a cluster that additionally includes Neolithic British individuals. This result is also evident in terms of absolute genetic differentiation, with low pairwise FST ~ 0.005 +- 0.002 between Neolithic Sardinian individuals and Neolithic western mainland European populations. Pairwise outgroup-f3 analysis shows a very similar pattern, with the highest values of f3 (i.e. most shared drift) being with Neolithic and Copper Age Iberia, gradually dropping off for temporally and geographically distant populations.

In explicit admixture models (using qpAdm, see Methods) the southern French Neolithic individuals (France-N) are the most consistent with being a single source for Neolithic Sardinia (p ~ 0:074 to reject the model of one population being the direct source of the other); followed by other populations associated with the western Mediterranean Neolithic Cardial Ware expansion.

sardinians-ancient-eef
Principal Components Analysis based on the Human Origins dataset. A: Projection of ancient individuals’ genotypes onto principal component axes de fined by modern Western Eurasians (gray labels).

Pervasive Western Hunter-Gatherer ancestry in Iberian/French/Sardinian population

Similar to western European Neolithic and central European Late Neolithic populations, ancient Sardinian individuals are shifted towards WHG individuals in the top two PCs relative to early Neolithic Anatolians Admixture analysis using qpAdm infers that ancient Sardinian individuals harbour HG ancestry (~ 17%) that is higher than early Neolithic mainland populations (including Iberia, ~ 8%), but lower than Copper Age Iberians (~ 25%) and about the same as Southern French Middle-Neolithic individuals (~ 21%).

sardinia-modern-ancient-nuragic-pca
Principal Components Analysis based on the Human Origins dataset. B: Zoom into the region most relevant for Sardinian individuals.

Continuity from Sardinia Neolithic through the Nuragic

We found several lines of evidence supporting genetic continuity from the Sardinian Neolithic into the Bronze Age and Nuragic times. Importantly, we observed low genetic differentiation between ancient Sardinian individuals from various time periods.

A qpAdm analysis, which is based on simultaneously testing f-statistics with a number of outgroups and adjusts for correlations, cannot reject a model of Neolithic Sardinian individuals being a direct predecessor of Nuragic Sardinian individuals (…) Our qpAdm analysis further shows that the WHG ancestry proportion, in a model of admixture with Neolithic Anatolia, remains stable at ~17% throughout three ancient time-periods.

sardinians-modern-ancient-pca-admixture
Present-day genetic structure in Sardinia reanalyzed with aDNA. A: Scatter plot of the rst two principal components trained on 1577 present-day individuals with grand-parental ancestry from Sardinia. Each individual is labeled with a location if at least 3 of the 4 grandparents were born in the same geographical location (\small” three letter abbreviations); otherwise with \x” or if grand-parental ancestry is missing with \?”. We calculated median PC values for each Sardinian province (large abbreviations). We also projected each ancient Sardinian individual on to the top two PCs (gray points). B/C: We plot f-statistics that test for admixture of modern Sardinian individuals (grouped into provinces) when using Nuragic Sardinian individuals as one source population. Uncertainty ranges depict one standard error (calculated from block bootstrap). Karitiana are used in the f-statistic calculation as a proxy for ANE/Steppe ancestry (Patterson et al., 2012).

Steppe influx in Modern Sardinians

While contemporary Sardinian individuals show the highest affinity towards EEF-associated populations among all of the modern populations, they also display membership with other clusters (Fig. 5). In contrast to ancient Sardinian individuals, present-day Sardinian individuals carry a modest “Steppe-like” ancestry component (but generally less than continental present-day European populations), and an appreciable broadly “eastern Mediterranean” ancestry component (also inferred at a high fraction in other present-day Mediterranean populations, such as Sicily and Greece).

Related

The genetic makings of South Asia – IVC as Proto-Dravidian

south-asian-language-families

Review (behind paywall) The genetic makings of South Asia, by Metspalu, Monda, and Chaubey, Current Opinion in Genetics & Development (2018) 53:128-133.

Interesting excerpts (emphasis mine):

(…) the spread of agriculture in Europe was a result of the demic diffusion of early Anatolian farmers, it was discovered that the spread of agriculture to South Asia was mediated by a genetically completely different farmer population in the Zagros mountains in contemporary Iran (IF). The ANI-ASI cline itself was interpreted as a mixture of three components genetically related to Iranian agriculturalists, Onge and Early and Middle Bronze Age Steppe populations (Steppe_EMBA).

The first ever autosomal aDNA from South Asia comes from Northern Pakistan (Swat Valley, early Iron Age). This study presented altogether 362 aDNA samples from the broad South and Central Asia and contributes substantially to our understanding of the evolutionary past of South and Central Asia. The study redefines the three genetic strata that form the basis of the Indian Cline. The Indus Periphery (IP) component is composed of (varying proportions of): first, IF, second, Ancient Ancestral South Asians (AASI), which represents an ancient branch of human genetic variation in Asia arising from a population split contemporaneous with the splits of East Asian, Onge and Australian Aboriginal ancestors and third, West_Siberian Hunter gatherers (WS_HG).

The authors argue that IP could have formed the genetic base of the Indus Valley Civilization (IVC). Upon the collapse of the IVC IP contributes to the formation of both ASI and ANI. ASI is formed as IP admixes further with AASI. ANI in turn forms when IP admixes with the incoming Middle and Late Bronze Age Steppe (Steppe_MLBA) component, (rather than the Steppe_EMBA groups suggested earlier)

ane-whg-ehg-chg-wshg-steppe
A sketch of the peopling history of South Asia. Depicting the full complexity of available reconstructions is not attempted. Placing of population labels does not indicate precise geographic location or range of the population in question. Rather we aim to highlight the essentials of the recent advancements in the field. We divide the scenario into three time horizons: Panels (a) before 10 000 BCE (pre agriculture era.); (b) 10 000 BCE to 3000 BCE (agriculture era) and (c) 3000 BCE to prehistoric era/modern era. (iron age).

Dating of the arrival of the Austro-Asiatic speakers in South Asia-based on Y chromosome haplogroup O2a1-M95 expansion estimates yielded dates between 3000 and 2000 BCE [30]. However, admixture LD decay-based approach on genome-wide data suggests the admixture between South Asian and incoming Austro-Asiatic speakers occurred slightly later between 1800 and 0 BCE (Tätte et al. submitted). It is interesting that while the mtDNA variants of the Mundas are completely South Asian, the Y chromosome variation is dominated at >60% by haplogroup O2a which is phylogeographically nested in East Asian-specific paternal lineages.

In India, the speakers of Tibeto-Burman (TB) languages live in the Seven Sisters States in Northeast India and in the very north of the country. Genetically they show a clear East Asian origin and around 20% of subsequent admixture with South Asians within the last 1000 years.The genetic flavour of East Asia in TB is different from that in Munda speakers as the best surrogates for the East Asian admixing component are contemporary Han Chinese.

I found the simplistic migration maps especially interesting to illustrate ancient population movements. The emergence of EHG is supposed to involve a WHG:ANE cline, though, and this isn’t clear from the map. Also, there is new information on what may be at the origin of WHG and Anatolian hunter-gatherers.

From the recent Reich’s session on South Asia at ISBA 8:

ani-asi-steppe-cline
– Tale of three clines, with clear indication that “Indus Periphery” samples drawn from an already-cosmopolitan and heterogeneous world of variable ASI & Iranian ancestry. (I know how some people like to pore over these pictures – so note red dots = just dummy data for illustration.)
– Some more certainty about primary window of steppe ancestry injection into S. Asia: 2000-1500 BC
Alexander M. Kim

Featured image: map of South Asian languages from http://llmap.org.

Related

Corded Ware—Uralic (I): Differences and similarities with Yamna

indo-european-uralic-migrations-corded-ware

This is the first of four posts on the Corded Ware—Uralic identification:

I was reading The Bronze Age Landscape in the Russian Steppes: The Samara Valley Project (2016), and I was really surprised to find the following excerpt by David W. Anthony:

The Samara Valley links the central steppes with the western steppes and is a north-south ecotone between the pastoral steppes to the south and the forest-steppe zone to the north [see figure below]. The economic contrast between pastoral steppe subsistence, with its associated social organizations, and forest-zone hunting and fishing economies probably explains the shifting but persistent linguistic border between forest-zone Uralic languages to the north (today largely displaced by Russian) and a sequence of steppe languages to the south, recently Turkic, before that Iranian, and before that probably an eastern dialect of Proto-Indo-European (Anthony 2007). The Samara Valley represents several kinds of borders, linguistic, cultural, and ecological, and it is centrally located in the Eurasian steppes, making it a critical place to examine the development of Eurasian steppe pastoralism.

uralic-languages-forest-zone-volga
Language map of the middle Volga-Ural region. After “Geographical Distribution of the Uralic Languages” by Finno-Ugrian Society, Helsinki, 1993.

Khokhlov (translated by Anthony) further insists on the racial and ethnic divide between both populations, Abashevo to the north, and Poltavka to the south, during the formation of the Abashevo – Sintashta-Potapovka community that gave rise to Proto-Indo-Iranians:

Among all cranial series in the Volga-Ural region, the Potapovka population represents the clearest example of race mixing and probably ethnic mixing as well. The cultural advancements seen in this period might perhaps have been the result of the mixing of heterogeneous groups. Such a craniometric observation is to some extent consistent with the view of some archaeologists that the Sintashta monuments represent a combination of various cultures (principally Abashevo and Poltavka, but with other influences) and therefore do not correspond to the basic concept of an archaeological culture (Kuzmina 2003:76). Under this option, the Potapovka-Sintashta burial rite may be considered, first, a combination of traits to guarantee the afterlife of a selected part of a heterogeneous population. Second, it reflected a kind of social “caste” rather than a single population. In our view, the decisive element in shaping the ethnic structure of the Potapovka-Sintashta monuments was their extensive mobility over a fairly large geographic area. They obtained knowledge of various cultures from the populations with whom they interacted.

steppe-lmba-sintashta-potapovka-filatovka
Late Middle Bronze Age cultures with the Proto-Indo-Iranian Sintashta-Potapovka-Filatovka group (shaded). After Anthony (2007 Figure 15.5), from Anthony (2016).

Interesting is also this excerpt about the predominant population in the Abashevo – Sintashta-Potapovka admixture (which supports what Chetan said recently, although this does not seemed backed by Y-DNA haplogroups found in the richest burials), coupled with the sign of incoming “Uraloid” peoples from the east, found in both Sintashta and eastern Abashevo:

The socially dominant anthropological component was Europeoid, possibly the descendants of Yamnaya. The association of craniofacial types with archaeological cultures in this period is difficult, primarily because of the small amount of published anthropological material of the cultures of steppe and forest belt (Balanbash, Vol’sko-Lbishche) and the eastern and southern steppes (Botai-Tersek). The crania associated with late MBA western Abashevo groups in the Don-Volga forest zone were different from eastern Abashevo in the Urals, where the expression of the Old Uraloid craniological complex was increased. Old Uraloid is found also on a single skull of Vol’sko-Lbishche culture (Tamar Utkul VII, Kurgan 4). Potentially related variants, including Mongoloid features, could be found among the Seima-Turbino tribes of the forest-steppe zone, who mixed with Sintashta and Abashevo. In the Sintashta Bulanova cemetery from the western Urals, some individuals were buried with implements of Seima-Turbino type (Khalyapin 2001; Khokhlov 2009; Khokhlov and Kitov 2009). Previously, similarities were noted between some individual skulls from Potapovka I and burials of the much older Botai culture in northern Kazakhstan (Khokhlov 2000a). Botai-Tersek is, in fact, a growing contender for the source of some “eastern” cranial features.

khvalynsk-yamna-srubna-facial-reconstruction
Facial reconstructions based on skulls from (a) Khvalynsk II Grave 24, a young adult male; (b) Poludin Grave 6, Yamnaya culture, a mature male (both by A. I. Nechvaloda); and (c) Luzanovsky cemetery, Srubnaya culture (by L. T. Yablonsky). In Khokhlov (2016).

The wave of peoples associated with “eastern” features can be seen in genetics in the Sintashta outliers from Narasimhan et al. (2018), and it probably will be eventually seen in Abashevo, too. These may be related to the Seima-Turbino international network – but most likely it is directly connected to Sintashta through the starting Andronovo and Seima-Turbino horizons, by admixing of prospective groups and small-scale back-migrations.

Corded Ware – Yamna similarities?

So, if peoples of north-eastern Europe have been assumed for a long time to be Uralic speakers, what is happening with the Corded Ware = IE obsession? Is it Gimbutas’ ghost possessing old archaeologists? Probably not.

It is about certain cultural similarities evident at first sight, which have been traditionally interpreted as a sign of cultural diffusion or migration. Not dissimilar to the many Bell Beaker models available, where each archaeologist is pushing certain differences, mixing what seemed reasonable, what still might seem reasonable, and what certainly isn’t anymore after the latest ancient DNA data.

kurgan-expansion
“European dialect” expansion of Proto-Indo-European according to Gimbutas (1963)

The initial models of Gimbutas, Kristiansen, or Anthony – which are known to many today – were enunciated in the infancy of archaeological studies in the regions, during and just after the fall of the USSR, and before many radiocarbon dates that we have today were published (with radiocarbon dating being still today in need of refinement), so it is only logical that gross mistakes were made.

We have similar gross mistakes related to the origins of Bell Beakers, and studying them was certainly easier than studying eastern data.

  • Gimbutas believed – based mainly on Kurgan-like burials – that Bell Beaker formed from a combination of Yamna settlers with the Vučedol culture, so she was not that far from the truth.
  • The expansion of Corded Ware from peoples of the North Pontic forest-steppe area, proposed by Gimbutas and later supported also by Kristiansen (1989) as the main Indo-European expansion – , is probably also right about the approximate origins of the culture. Only its ‘Indo-European’ nature is in question, given the differences with Khvalynsk and Yamna evolution.
  • Anthony only claimed that Yamna migrants settled in the Balkans and along the Danube into the Hungarian steppes. He never said that Corded Ware was a Yamna offshoot until after the first genetic papers of 2015 (read about his newest proposal). He initially claimed that only certain neighbouring Corded Ware groups “adopted” Indo-European (through cultural diffusion) because of ‘patron-client’ relationships, and was never preoccupied with the fate of Corded Ware and related cultures in the east European forest zone and Finland.

So none of them was really that far from the true picture; we might say a lot people are more way off the real picture today than the picture these three researchers helped create in the 1990s and 2000s. Genetics is just putting the last nail in the coffin of Corded Ware as a Yamna offshoot, instead of – as we believed in the 2000s – to Vučedol and Bell Beaker.

So let’s revise some of these traditional links between Corded Ware and Yamna with today’s data:

Archaeology

Even more than genetics – at least until we have an adequate regional and temporary sampling – , archaeological findings lead what we have to know about both cultures.

It is essential to remember that Corded Ware, starting ca. 3000/2900 BC in east-central Europe, has been proposed to be derived from Early Yamna, which appeared suddenly in the Pontic-Caspian steppes ca. 3300 BC (probably from the late Repin expansion), and expanded to the west ca. 3000.

Early Yamna is in turn identified as the expanding Late Proto-Indo-European community, which has been confirmed with the recent data on Afanasevo, Bell Beaker, and Sintashta-Potapovka and derived cultures.

The question at hand, therefore, is if Corded Ware can be considered an offshoot of the Late PIE community, and thus whether the CWC ethnolinguistic community – proven in genetics to be quite homogeneous – spoke a Late PIE dialect, or if – alternatively – it is derived from other neighbouring cultures of the North Pontic region.

NOTE. The interpretation of an Indo-Slavonic group represented by a previous branching off of the group is untenable with today’s data, since Indo-Slavonic – for those who support it – would itself be a branch of Graeco-Aryan, and Palaeo-Balkan languages expanded most likely with West Yamna (i.e. R1b-L23, mainly R1b-Z2103) to the south.

The convoluted alternative explanation would be that Corded Ware represents an earlier, Middle PIE branch (somehow carrying R1a??) which influences expanding Late PIE dialects; this has been recently supported by Kortlandt, although this simplistic picture also fails to explain the Uralic problem.

Kurgans: The Yamna tradition was inherited from late Repin, in turn inherited from Khvalynsk-Novodanilovka proto-Kurgans. As for the CWC tradition, it is unclear if the tumuli were built as a tradition inherited from North and West Pontic cultures (in turn inherited or copied from Khvalynsk-Novodanilovka), such as late Trypillia, late Kvityana, late Dereivka, late Sredni Stog; or if they were built because of the spread of the ‘Transformation of Europe’, set in motion by the Early Yamna expansion ca. 3300-3000 BC (as found in east-central European cultures like Coţofeni, Lizevile, Șoimuș, or the Adriatic Vučedol). My guess is that it inherits an older tradition than Yamna, with an origin in east-central Europe, because of the mound-building distribution in the North Pontic area before the Yamna expansion, but we may never really know.

pit-graves-central-europe-cwc
Distribution of Pit-Grave burials west of the Black Sea likely dating to the 2nd half of the IVth millennium BC (triangles: side-crouched burials; filled circles: supine extended burials; open circles: suspected). Frînculeasa, Preda, and Heyd (2015)

Burial rite: Yamna features (with regional differences) single burials with body on its back, flexed upright knees, poor grave goods, common orientation east-west (heads to the west) inherited from Repin, in turn inherited from Khvalynsk-Novodanilovka. CWC tradition – partially connected to Złota and surrounding east-central European territories (in turn from the Khvalynsk-Novodanilovka expansion) – features single graves, body in fetal position, strict gender differentiation – men on the right, women on the left -, looking to the south, graves with standardized assemblages (objects representing affirmation of battle, hunting, and feasting). The burial rites clearly represent different ideologies.

pit-grave-burial-schemes
Left: Pit-Grave burial types expanded with Khvalynsk-Novodanilovka. Right: Pit-Grave burial types associated with the Yamna expansion and influence. Frînculeasa, Preda, and Heyd (2015)

Corded decoration: Corded ware decoration appears in the Balkans during the 5th millennium, and represents a simple technique whereby a cord is twisted, or wrapped around a stick, and then pressed directly onto the fresh surface of a vessel leaving a characteristic decoration. It appears in many groups of the 5th and 4th millennium BC, but it was Globular Amphorae the culture which popularized the drinking vessels and their corded ornamentation. It appears thus in some regional groups of Yamna, but it becomes the standard pottery only in Corded Ware (especially with the A-horizon), which shows continuity with GAC pottery.

corded-ware-first-horizon
Origins of the first Corded Ware horizon (5th millennium BC) after the Khvalynsk-Novodanilovka expansion. Corded Ware (circles) and horse-head scepters (rectangles) and other steppe elements (triangles). Image from Bulatović (2014).

Economy: Yamna expands from Repin (and Repin from Khvalynsk-Novodanilovka) as a nomadic or semi-nomadic purely pastoralist society (with occasional gathering of wild seeds), which naturally thrives in the grasslands of the Pontic-Caspian, lower Danube and Hungarian steppes. Corded Ware shows agropastoralism (as late Eneolithic forest-steppe and steppe groups of eastern Europe, such as late Trypillian, TRB, and GAC groups), inhabits territories north of the loess line, with heavy reliance of hunter-gathering depending on the specific region.

Cattle herding: Interestingly, both west Yamna and Corded Ware show more reliance on cattle herding than other pastoralist groups, which – contrasted with the previous Eneolithic herding traditions of the Pontic-Caspian steppe, where sheep-goats predominate – make them look alike. However, the cattle-herding economy of Yamna is essential for its development from late Repin and its expansion through the steppes (over western territories practising more hunter-gathering and sheep-goat herding economy), and it does not reach equally the Volga-Ural region, whose groups keep some of the old subsistence economy (read more about the late Repin expansion). Corded Ware, on the other hand, inherits its economic strategy from east European groups like TRB, GAC, and especially late Trypillian communities, showing a predominance of cattle herding within an agropastoral community in the forest-steppe and forest zones of Volhynia, Podolia, and surrounding forest-steppe and forest regions.

yamna-scheme
Scheme of interlinked socio-economic-ideological innovations forming the Yamnaya. Frînculeasa, Preda, and Heyd (2015)

Horse riding: Horse riding and horse transport is proven in Yamna (and succeeding Bell Beaker and Sintashta), assumed for late Repin (essential for cattle herding in the seas of grasslands that are the steppes, without nearby water sources), quite likely during the Khvalynsk expansion (read more here), and potentially also for Samara, where the predominant horse symbolism of early Khvalynsk starts. Corded Ware – like the north Pontic forest-steppe and forest areas during the Eneolithic – , on the other hand, does not show a strong reliance on horse riding. The high mobility and short-term settlements characteristic of Corded Ware, that are often associated with horse riding by association with Yamna, may or may not be correct, but there is no need for horses to explain their herding economy or their mobility, and the north-eastern European areas – the one which survived after Bell Beaker expansion – did certainly not rely on horses as an essential part of their economy.

NOTE: I cannot think of more supposed similarities right now. If you have more ideas, please share in the comments and I will add them here.

Genetic similarities

EHG: This is the clearest link between both communities. We thought it was related to the expansion of ANE-related ancestry to the west into WHG territory, but now it seems that it will be rather WHG expanding into ANE territory from the Pontic-Caspian region to the east (read more on recent Caucasus Neolithic, on , and on Caucasus HG).

NOTE. Given how much each paper changes what we know about the Palaeolithic, the origin and expansion of the (always developing) known ancestral components and specific subclades (see below) is not clear at all.

CHG: This is the key link between both cultures, which will delimit their interaction in terms of time and space. CHG is intermediate between EHG and Iran N (ca. 8000 BC). The ancestry is thus linked to the Caucasus south of the steppe before the emergence of North Pontic (western) and Don-Volga-Ural (eastern) communities during the Mesolithic. The real question is: when we have more samples from the steppe and the Caucasus during the Neolithic, how many CHG groups are we going to find? Will the new specific ancestral components (say CHG1, CHG2, CHG3, etc.) found in Yamna (from Khvalynsk, in the east) and Corded Ware (probably from the North Pontic forest-steppe) be the same? My guess is, most likely not, unless they are mediated by the Khvalynsk-Novodanilovka expansion (read more on CHG in the Caucasus).

yamnaya-chg-ancestry
Formation of Yamna and CHG contribution, in Damgaard et al. (Science 2018). A 10-leaf model based on combining the models in Fig. S16 and Fig. S19 and re-estimating the model parameters.

WHG/EEF: This is the obvious major difference – known today – in the formation of both communities in the steppe, and shows the different contacts that both groups had at least since the Eneolithic, i.e. since the expansion of Repin with its renewed Y-DNA bottleneck, and probably since before the early Khvalynsk expansion (read more on Yamna-Corded Ware differences contrasting with Yamna-Afanasevo, Yamna-Bell Beaker, and Yamna-Sintashta similarities).

NOTE 1. Some similarities between groups can be seen depending on the sampled region; e.g. Baltic groups show more similarities with southern Pontic-Caspian steppe populations, probably due to exogamy.

yamna-corded-ware-diff-qpgraph
Tested qpGraph model in Tambets et al. (2018). The qpGraph model fitting the data for the tested populations. “Colour codes for the terminal nodes: pink—modern populations (‘Population X’ refers to test population) and yellow—ancient populations (aDNA samples and their pools). Nodes coloured other than pink or yellow are hypothetical intermediate populations. We putatively named nodes which we used as admixture sources using the main recipient among known populations. The colours of intermediate nodes on the qpGraph model match those on the admixture proportions panel.”

NOTE 2. We have this information on the differences in “steppe ancestry” between Yamna and Corded Ware, compared to previous studies, because now we have more samples of neighbouring, roughly contemporaneous Eneolithic groups, to analyse the real admixture processes. This kind of fine scale studies is what is going to show more and more differences between Khvalynsk-Yamna and Sredni Stog-Corded Ware as more data pours in. The evolution of both communities in archaeology and in PCA (see below) is probably witness to those differences yet to be published.

R1: Even though some people try very hard to think in terms of “R1” vs. (Caucasus) J or G or any other upper clade, this is plainly wrong. It is possible, given what we know now, that Q1a2-M242 expanded ANE ancestry to the west ca. 13000 BC, while R1b-P279 expanded WHG ancestry to the east with the expansion of post-Swiderian cultures, creating EHG as a WHG:ANE cline. The role of R1a-M459 is unknown, but it might be related to any of these migrations, or others (plural) along northern Eurasia (read more on the expansion of R1b-P279, on Palaeolithic Q1a2, and on R1a-M417).

NOTE. I am inclined to believe in a speculative Mesolithic-Early Neolithic community involving Eurasiatic movements accross North Eurasia, and Indo-Uralic movements in its western part, with the last intense early Uralic-PIE contacts represented by the forming west (Mariupol culture) and east (Don-Volga-Ural cultures, including Samara) communities developing side by side. Before their known Eneolithic expansions, no large-scale Y-DNA bottleneck is going to be seen in the Pontic-Caspian steppe, with different (especially R1a and R1b subclades) mixed among them, as shown in North Pontic Neolithic, Samara HG, and Khvalynsk samples.

PCA-trypillia-greece-neolithic-outlier-anatolian
Image modified from Wang et al. (2018). Samples projected in PCA of 84 modern-day West Eurasian populations (open symbols). Previously known clusters have been marked and referenced. Marked and labelled are the Balkan samples referenced in this text An EHG and a Caucasus ‘clouds’ have been drawn, leaving Pontic-Caspian steppe and derived groups between them. See the original file here.

Corded Ware and ‘steppe ancestry’

If we take a look at the evolution of Corded Ware cultures, the expansion of Bell Beakers – dominated over most previous European cultures from west to east Europe – influenced the development of the whole European Bronze Age, up to Mierzanowice and Trzciniec in the east.

The only relevant unscathed CWC-derived groups, after the expansion of Sintashta-Potapovka as the Srubna-Andronovo horizon in the Eurasian steppes, were those of the north-eastern European forest zone: between Belarus to the west, Finland to the north, the Urals to the east, and the forest-steppe region to the south. That is, precisely the region supposed to represent Uralic speakers during the Bronze Age.

This inconsistency of steppe ancestry and its relation with Uralic (and Balto-Slavic) peoples was observed shortly after the publication of the first famous 2015 papers by Paul Heggarty, of the Max-Planck Institute for Evolutionary Anthropology (read more):

Haak et al. (2015) make much of the high Yamnaya ancestry scores for (only some!) Indo-European languages. What they do not mention is that those same results also include speakers of other languages among those with the highest of all scores for Yamnaya ancestry. Only these are languages of the Uralic family, not Indo-European at all; and their Yamnaya-ancestry signals are far higher than in many branches of Indo-European in (southern) Europe. Estonian ranks very high, while speakers of the very closely related Finnish are curiously not shown, and nor are the Saami. Hungarian is relevant less directly since this language arrived only c. 900 AD, but also high.

uralic-steppe-ancestry

These data imply that Uralic-speakers too would have been part of the Yamnaya > Corded Ware movement, which was thus not exclusively Indo-European in any case. And as well as the genetics, the geography, chronology and language contact evidence also all fit with a Yamnaya > Corded Ware movement including Uralic as well as Balto-Slavic.

Both papers fail to address properly the question of the Uralic languages. And this despite — or because? — the only Uralic speakers they report rank so high among modern populations with Yamnaya ancestry. Their linguistic ancestors also have a good claim to have been involved in the Corded Ware and Yamnaya cultures, and of course the other members of the Uralic family are scattered across European Russia up to the Urals.

NOTE. Although the author was trying to support the Anatolian hypothesis – proper of glottochronological studies often published from the Max Planck Institute – , the question remains equally valid: “if Proto-Indo-European expands with Corded Ware and steppe ancestry, what is happening with Uralic peoples?”

For my part, I claimed in my draft that ancestral components were not the only relevant data to take into account, and that Y-DNA haplogroups R1a and R1b (appearing separately in CWC and Yamna-Bell Beaker-Afanasevo), together with their calculated timeframes of formation – and therefore likely expansion – did not fit with the archaeological and linguistic description of the spread of Proto-Indo-European and its dialects.

In fact, it seemed that only one haplogroup (R1b-M269) was constantly and consistenly associated with the proposed routes of Late PIE dialectal expansions – like Anthony’s second (Afanasevo) and third (Lower Danube, Balkan) waves. What genetics shows fits seamlessly with Mallory’s association of the North-West Indo-European expansion with Bell Beakers (read here how archaeologists were right).

balanovksy-yamnaya-ancestry
Map of the much beloved steppe (or “Yamnaya”) ancestry in modern populations, by Balanovsky. Modified from Klejn (2017).

More precise inconsistencies were observed after the publication of Olalde et al. (2017) and Mathieson et al. (2017), by Volker Heyd in Kossinna’s smile (2017). Letting aside the many details enumerated (you can read a summary in my latest draft), this interesting excerpt is from the conclusion:

NOTE. An open access ealier draft version of the paper is offered for download by the author.

Simple solutions to complex problems are never the best choice, even when favoured by politicians and the media. Kossinna also offered a simple solution to a complex prehistoric problem, and failed therein. Prehistoric archaeology has been aware of this for a century, and has responded by becoming more differentiated and nuanced, working anthropologically, scientifically and across disciplines (cf. Müller 2013; Kristiansen 2014), and rejecting monocausal explanations. The two aDNA papers in Nature, powerful and promising as they are for our future understanding, also offer rather straightforward messages, heavily pulled by culture-history and the equation of people with culture. This admittedly is due partly to the restrictions of the medium that conveys them (and despite the often relevant additional detail given as supplementary information, which is unfortunately not always given full consideration).

While I have no doubt that both papers are essentially right, they do not reflect the complexity of the past. It is here that archaeology and archaeologists contributing to aDNA studies find their role; rather than simply handing over samples and advising on chronology, and instead of letting the geneticists determine the agenda and set the messages, we should teach them about complexity in past human actions and interactions. If accepted, this could be the beginning of a marriage made in heaven, with the blessing smile of Gustaf Kossinna, and no doubt Vere Gordon Childe, were they still alive, in a reconciliation of twentieth- and twenty-first-century approaches. For us as archaeologists, it could also be the starting point for the next level of a new archaeology.

heyd-yamnaya-expansion
Main distribution of Yamnaya kurgans in the Pontic-Caspian steppe of modern day Russia, Ukraine, and Kazakhstan, and its western branch in modern south-east European countries of Romania, Bulgaria, Serbia, and Hungary, with numbers of excavated kurgans and graves given. Picture: Volker Heyd (2018).

The question was made painfully clear with the publication of Olalde et al. (2018) & Mathieson et al. (2018), where the real route of Yamna expansion into Europe was now clearly set through the steppes into the Carpathian basin, later expanded as Bell Beakers.

This has been further confirmed in more recent papers, such as Narasimhan et al. (2018), Damgaard et al. (2018), or Wang et al. (2018), among others.

However, the discussion is still dominated by political agendas based on prevalent Y-DNA haplogroups in modern countries and ethnic groups.

Related

Bayesian estimation of partial population continuity by using ancient DNA and spatially explicit simulations

europe-palaeolithic-neolithic

Open access Bayesian estimation of partial population continuity by using ancient DNA and spatially explicit simulations, by Silva et al., Evolutionary Applications (2018).

Abstract (emphasis mine):

The retrieval of ancient DNA from osteological material provides direct evidence of human genetic diversity in the past. Ancient DNA samples are often used to investigate whether there was population continuity in the settlement history of an area. Methods based on the serial coalescent algorithm have been developed to test whether the population continuity hypothesis can be statistically rejected by analysing DNA samples from the same region but of different ages. Rejection of this hypothesis is indicative of a large genetic shift, possibly due to immigration occurring between two sampling times. However, this approach is only able to reject a model of full continuity model (a total absence of genetic input from outside), but admixture between local and immigrant populations may lead to partial continuity. We have recently developed a method to test for population continuity that explicitly considers the spatial and temporal dynamics of populations. Here we extended this approach to estimate the proportion of genetic continuity between two populations, by using ancient genetic samples. We applied our original approach to the question of the Neolithic transition in Central Europe. Our results confirmed the rejection of full continuity, but our approach represents an important step forward by estimating the relative contribution of immigrant farmers and of local hunter‐gatherers to the final Central European Neolithic genetic pool. Furthermore, we show that a substantial proportion of genes brought by the farmers in this region were assimilated from other hunter‐gatherer populations along the way from Anatolia, which was not detectable by previous continuity tests. Our approach is also able to jointly estimate demographic parameters, as we show here by finding both low density and low migration rate for pre‐Neolithic hunter‐gatherers. It provides a useful tool for the analysis of the numerous aDNA datasets that are currently being produced for many different species.

central-european-neolithic
A) Different zones defined for computing proportions of ancestry in Central Europeans 4,500 BP. B) Schematic representation of various population contributions. C) Mean proportions of ancestry from the various PHG zones (A+B+C+D) in Central European populations from zone A at the end of the Neolithic transition 4,500 BP, computed for autosomal and mitochondrial markers.

Relevant excerpts:

Our results are in general accordance with two distinct ancestry components that have previously been detected at the continental scale by Lazaridis, Patterson et al. (2014): the “early European farmer” (EEF), which corresponds here to the NFA from Anatolia (zone C in Figure 3), and the “West European hunter-gatherer” (WHG), which corresponds here to the PHG from zones A and B in Figure 3. Notably, the contribution of an Ancient North Eurasians (ANE) component is not included in our model as we did not consider potential post-Neolithic immigration waves, which could have contributed to the modern European genetic pool, such as the wave that came from the Pontic steppes and was associated with the Yamnaya culture (Haak, Lazaridis et al. 2015). Without considering the ANE ancestry component, our estimate of the autosomal genetic contribution of Early farmers to the gene pool of Central European populations (25%) tends to be lower than the EEF ancestry estimated in most modern Western European populations, but is of the same order than the estimations in modern Estonians and in the ancient Late Neolithic genome “Karsdorf” from Germany (Lazaridis, Patterson et al. 2014, Haak, Lazaridis et al. 2015). Note that the contribution of hunter-gatherers to Neolithic communities appears to be variable in different regions of Europe (Skoglund, Malmstrom et al. 2012, Brandt, Haak et al. 2013, Lazaridis, Patterson et al. 2014), while we computed an average value for Central Europe. Moreover, we computed the ancestry of the two groups at the end of the Neolithic period while previous studies estimated it in modern times. Finally, previous studies used molecular information to directly estimate admixture proportions, while we use molecular information to estimate the model parameters and, then, we computed the expected genetic contributions of both groups using the best parameters, without using molecular information during this second step. Model assumptions may thus influence the inferences on the relative genetic contribution of both groups. In particular, we made the assumption of a uniform expansion of NFA with constant and similar assimilation of PHG over the whole continent but spatio-temporally heterogeneous environment, variable assimilation rate and long distance dispersal may have played an important role. The effects of those factors should be investigated in future studies.