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

Featuredyamnaya-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 Even my post “Steppe ancestry” step by step from a year ago is already outdated.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.

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

Sredni Stog, Proto-Corded Ware, and their “steppe admixture”

steppe-eneolithic-migrations

Once the haplogroups of the announced West Yamna and Yamna settlers in Hungary and Khvalynsk from Ekaterinovka appear, it is to be expected that there won’t be much discussion on the Y-DNA bottlenecks that affected Khvalynsk – Yamna migrations.

So let’s cut to the chase and see where Corded Ware peoples (mainly of R1a-Z645 subclades) got their so-called “steppe admixture” different from that of Yamna. Because, as you might have realized by now, Sredni Stog – and consequently Corded Ware – remains nowadays an undefined (archaeological) mess.

Rassamakin explains it quite well, in the chapter Eneolithic of the Black Sea Steppe; In Levine M., Rassamakin Yu., Kislenko A. and Tatarintseva N., 1999. Late Prehistoric Exploitation of the Eurasian Steppe. McDonald Institute Monographs, University of Cambridge.

NOTE. These are only certain relevant excerpts. The whole chapter is worth a thorough read, whatever position you hold regarding steppe expansions. In fact, he supports the Skelya cultural (macro-)group instead of Khvalynsk-Novodanilovka vs. Sredni Stog, he does not believe in significant expansions from the east (but in local movements and a ‘general evolution’ of Pontic-Caspian steppe cultures to Early Yamna), and offers e.g. the presence of copper and trade from the west (and its poor presence in the east) as an example of the importance of the North Pontic area vis-à-vis Khvalynsk/Repin. Not an interested party in supporting Gimbutas or Anthony, then, if you fear that.

Cultural groups in the North Pontic area

Telegin divided the Sredny Stog culture into three local variants – the Dnepr Culture variant, the Oskol-Donets (Aleksandriya) Culture variant, and the Lower Don (Konstantinovka) Culture variant. He elaborated a periodization based on the evolution of decorative motifs in the pottery assemblages.

At first, the internal contradictions of the Sredny Stog culture were not accorded particular prominence, despite clear intimations of problems when, for example, sites like the settlement of Konstantinovka on the Lower Don, was identified as actually belonging to another, independent culture (Kiyashko 1974). The first real blow to the integrity of the Sredny Stog culture was dealt by Telegin himself, when he removed five Novodanilovka-type sites, and accorded them the status of an independent cultural phenomenon (Telegin 1985a). Until that point, sites of this type had were customarily considered to be within the framework of the late group of Sredny Stog cemeteries, despite having been for long regarded by some as representative of an earlier, independent cultural group (Movsha & Chebotarenko 1969; Zbenovich 1973, 74-5; Gimbutas, Merpert and Danilenko passim). Indeed, it was unclear why these cemeteries had initially been assigned to the Late, rather than the Early, Sredny Stog culture. Now these sites were mechanically stripped out of the one system, but their place in the new system was not clearly defined.

rassamakin-skelya-culture
Rassamakin (1999) concept of cultural development of burial rituals in the North Pontic steppe.

Thus a paradox arose. Sites that had served to a considerable extent as the initial basis for the Sredny Stog culture, for the elaboration of its periodization and chronology, were now accepted as forming the core of an essentially different culture. Because of this, by the mid 1980s, both the Sredny Stog culture and the Eneolithic systematization as a whole were becoming rather amorphous. Essentially, the Sredny Stog culture was associated in the minds of many researchers solely with the settlement site at Dereivka, while they had only a confused and indistinct idea of the nature of early Sredny Stog sites. (…) Ultimately a situation developed where all attempts to view new evidence, new local groups, or even cultures through the prism of the Sredny Stog culture were futile, since researchers were unclear about of the essence of the culture itself, and often qualified themselves in footnotes with references to ‘preCorded Ware’ or ‘Corded Ware’ stages, or by relating their observations back directly to the specific sites of Sredny Stog II or Dereivka.

Thus, in the Middle Eneolithic, a number of independent cultures (Kvityana, Repin, Konstantinovka, and, to some degree, Dereivka, Cernavoda and Lower Mikhailovka) emerged in the region that had in the Early Eneolithic been occupied by the Skelya culture, either as lineal successors to this culture or under its influence. But the principal stimuli in this period were the Tripolye tribes, direct imports from whom reach the southern zone of the Dnepr left bank.

It is apparent that, for all their conceptual differences, if we remove Danilenko’s subdivisions, Telegin’s and Danilenko’s models are identical in terms of site periodization and sequence: first Kvityana, then Sredny Stog II, and finally Dereivka.

The North Pontic area in the Eneolithic (4000-3500 BC)

kvityana-dereivka-repin-trypolie-maykop
The Kvityana and Dereivka cultures in relation to other sites: 1) Molyukhov Bugor (settlement); 2) Dereivka (settlement); 3) Aleksandriya (settlement); 4) Minevsky Yar (settlement); 5) Khutor Repin (settlement).

Tripolye influence is seen most clearly in the development of the Lower Mikhailovka culture and a new burial rite which spread as far as the Molochnaya. Changes are apparent in kurgan architecture; that is, in the construction of stone chambers, sanctuaries comprising upright elements, and ring-shaped ditches (Rassamakin 1990; 1993; 1994; Pleshivenko & Rassamakin 1994 ). Lower Mikhailovka sites in the northwestern Black Sea coast region are known by a whole series of different designations, one of which, as I have already noted above, is ‘the Bessarabian variant of the Cernavoda I culture’ (Manzura 1993).

The formation of the Kvityana culture should be considered both in the context of the development of the Lower Mikhailovka culture, and in terms of the influence of the Sredny Stog II pottery assemblage. The first is manifested in the development of the kurgan ritual itself, with such structural elements as cromlechs, orthostats and stone cists. These are most apparent to the south, in the zone of contact with the Lower Mikhailovka culture. The second is apparent in the similarity between Kvityana pottery and Sredny Stog II pottery, notably in a number of shared compositional and technical elements, despite the fact that the shapes, techniques and style are all quite different.

As a whole, the Kvityana culture is notably conservative and archaic in appearance; this is manifest both in the preservation of a burial rite involving a supine position, and in the appearance of the pottery which, on the basis of the absence of corded or caterpillar track decoration, was until recently considered the earliest Sredny Stog ware.

(…) we still lack sufficient evidence to trace in detail the path by which the Kvityana culture spread from the Dnepr into the Dnestr-Danube region. The southern steppe route is excluded, but Kvityana sites are recorded on the Southern Bug, in the Dnestr region, and even along the forest-steppe boundary on the Prut Gudging by the numerous excavations of kurgans in this belt. This route in some respects repeats that along which the Skelya elite groups moved. Southward movement along the Southern Bug and its tributaries into the steppe zone is indicated only by isolated sites, the number of which is far smaller than in the Dnestr-Danube region, despite the intensive excavation of kurgans in this region. Evidence for Kvityana penetration into the northwestern Black Sea coast is provided by the appearance in Usatovo assemblages of typical Kvityana figural tubular bone beads, with diagnostic lateral notches on the sides (Malyukevich & Petrenko 1993).

kvityana-cucuteni-tripolye-expansions
Expansions of Kvityana and Trypillia cultures. Rassamakin (1999)

[The Dereivka] culture is currently only known only from settlement material, notably from sites in the Dnepr region (Dereivka and Molyukhov Bugor), but also from typologically distinctive pottery in the Eneolithic layer of the settlement of Aleksandriya on the Oskol. Dereivka culture pottery has also been recorded at a number of locations in the forest-steppe Dnepr region and the Seversky Donets, at Tetyanchino, Kamennye Pataki, and Minevsky Yar. The ceramic assemblage is well-defined and easily recognizable: vessels consistently display a weak profile and slightly elongated proportions, with high, straight mouths, evenly cut off at the rim, and conical bases (Fig. 3.23). The Dereivka culture occupies the southern part of the forest-steppe region and is bounded to the south by the Kvityana culture.

Telegin rightly noted that Dereivka and Kvityana pottery bore some resemblance to one another. Several fragments of the latter were found in the Dereivka assemblage, and provide evidence for the contemporaneous existence of the two cultures. The Molyukhov Bugor pottery assemblage stands out in terms of a prevalence of pottery with corded decoration, which only occurs in insignificant amounts at Dereivka and Aleksandriya. However, artefactual analysis has not produced any clear guidance for a chronological organization of these sites, as was postulated by Telegin.

sredni-stog-yamnaya
Rassamakin’s (1999) periodization of the North Pontic cultures

Late Phase and Final Eneolithic (3500-3000 BC)

In the Dnestr region, southward pressure from Tripolye led to the formation of, firstly, Vykhvatinsk-type sites, and then, in the steppe zone, Usatovo-type sites, which had undoubtedly absorbed some features of the Lower Mikhailovka culture. In the Prut and Middle Dnestr regions, sites of the Gordineşti (Kasperovkao) types are formed (these correspond, in the Romanian Prut region and on the Siret, to sites of the Horodiştea-Erbiceni type, and on the Lower Danube to the Cernavoda III culture: Morintz & Roman 1968; Dinu 1980; 1987). Movsha considers that sites of this type (Kasperovkao in her terminology) also occur in the Southern Bug region.

Sofievka-type sites emerge in the forest-steppes of the Middle Dnepr. A number of researchers (Zbenovich, Dergachev, and Sorokin), taking account of the change in the Tripolye culture at stage C2, propose a special division, considering sites of this period alone as ‘Late Tripolye’. In their view (with which I agree), stage Cl in culture-historical terms still corresponds to ‘Middle Tripolye’.

(…) existing evidence allows us to put forward the following scheme (Fig. 3.49:2). To the east of the Usatovo sites, from the lower reaches of the Southern Bug to the Azov region, encroaching on the Crimean steppes, the Lower Mikhailovka culture remains intact. To the north, upstream along the Dnepr and its tributaries, the Kvityana culture survives in its initial core zone. Between the Southern Bug and the Dnepr, in the contact zone between the three cultures (Tripolye, Lower Mikhailovka and Kvityana) the Dnepr-Bug group of sites emerges, displaying mixed features (Nikolova & Rassamakin 1985; Rassamakin 1988) Tripolye influence on the Dereivka culture appears to increase, as manifested in the appearance of late cultural elements (corded decoration, plastic art, bowls). The fate of the Pivikha culture is unclear. On the Lower Don, the late phase of the Konstantinovka culture (corresponding to the settlements of Konstantinovka and Razdorskoe I: Level 7) continued.

The final stage

The final stage of this period is characterized by two waves of migration, which properly speaking conclude the development of the Eneolithic.(…)

The first migration is connected with the breakdown of that system of Late Tripolye forest-steppe sites of the Prut-Dnestr and Southern Bug regions, dealt with by Movsha within the framework of the Kasperovo local group (and termed Gordineşti by others such as Dergachev, Manzura, and Petrenko). Almost all researchers into the Tripolye culture note the widespread occurrence of diagnostic elements of this group in the south, in the zone of the Usatovo sites and, in the east and southeast, towards the Dnepr and its left bank (Movsha 1984; 1990; 1993; Subbotin & Petrenko 1986; Manzura 1990a). (…)

The migrational wave that left Zhivotilovo-Volchanskoe-type burials in the steppe also linked up the forest-steppe Bug, Dnestr, and Prut regions with the Lower Don region, and, possibly with the North Caucasus, where the late stage of the Maikop culture (the Novosvobodnaya sites) continued. The identical rites of the Maikop culture and Zhivotilovo-Volchanskoe sites makes it difficult to establish the direction of migration, or which was the active side in the process. A number of researchers have given precedence to the Maikop culture. But the spread of the Tripolye assemblage unambiguously indicates the active involvement of the Tripolye tribes.

north-pontic-kvityana-dereivka
The system of the latest Eneolithic Pointic cultures and the sites of the Zhivotilovo-Volchanskoe type: 1) Volchanskoe; 2) Zhivotilovka; 3) Vishnevatoe; 4) Koisug

The second migration, at the very end of the Eneolithic, is connected with the spread of the Repin culture (in its second phase) from the Middle Don. Sinyuk defined three main directions: north, to the Upper Don; southwest, into the Dnepr region; and south, to the Lower Don and the Lower Volga. Trifonov considers this broad expansion of the Repin culture to be colonization (Trifonov 1996). The Repin culture level at Razdorskoe I (Razdorskoe I: Level 8) overlies the Konstantinovka levels (Levels 6 and 7), signalling that the Konstantinovka culture had apparently ceased to exist (Kiyashko 1994, 80). It seems that the expansion of the Repin culture is also associated with a reduction in the territorial extent of the Kvityana and Dereivka cultures. Repin burial assemblages, settlements and temporary camps appear in the Seversky Donets basin and in the Eastern Azov region (at Trekhizbenka, Kapitanovo, Aleksandriya, and Razdolnoe). The same complexes are also widely distributed towards the Dnepr (Marina 1992). The most striking western manifestation of Repin elements is seen in the upper horizon of the middle level of the Mikhailovka settlement (Lagodovska et al. 1962, 39-46).

Khvalynsk-Yamna and Sredni Stog-Corded Ware

We already know that Ukraine Eneolithic samples showed steppe ancestry and had apparently began a process of convergence coinciding with (or after) the first Khvalynsk-related migrations. It is unclear what had happened before (i.e. how much “CHG ancestry” was absorbed by Ukraine Neolithic groups in their transition to the Eneolithic before ca. 4500 BC), although in principle we can assume that all Caucasus-related admixture received by North Pontic cultures ca. 4500-4000 BC was mediated by westward movements from Khvalynsk-related peoples.

PCA-caucasus-lola-ane-chg
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. An EHG and a Caucasus ‘clouds’ have been drawn, leaving Pontic-Caspian steppe and derived groups between them.See the original file here.

Contacts with (and later absorption of) Khvalynsk-Novodanilovka-related migrants, as well as heir cultures, like those in the steppe adjacent to the Black Sea coast, and also direct contacts with Caucasus-related populations through Zhivotilovo-Volchanskoe can justify a greater contribution of CHG ancestry ca. 4000-3500 BC. Close contacts with Cucuteni-Trypillia (through Mikhailovka and maybe Kvityana, possibly with WHG and CHG admixture related to Khvalynsk-Novodanilovka) and GAC peoples to the north are the obvious source of further similarities with Yamna. Distinct similarities, that is, if we take into account the different sources and timing of such ancestral components, and Y-chromosome bottlenecks…

Therefore, after a process of convergence ca. 4500-4000 BC, and potentially more contacts with late Eneolithic North Pontic steppe cultures ca. 4000-3500 BC, Proto-Corded Ware peoples must have finally spread from the northernmost (forest-steppe) areas previously occupied by Dereivka, Pivikha, or Sofievka groups from ca. 3300 BC onwards – a date roughly coincident with the expansion of late Khvalynsk/Repin to the west developing the Early Yamna culture, with which it likely entered in contact (hence potentially a source for further admixture convergence ca. 3500-3000 BC).

Only later happened the great migration ca. 3000-2800 BC of Classical Corded Ware culture migrants, at the same time as Early Yamna migrants expanded to the west, and some groups also to the north along the Prut (possibly directly connected to the admixture found in the two Baltic LN/CWC ‘outliers’).

steppe-chalcolithic-migrations
Steppe-related migrations ca. 3100-2600 BC with tentative linguistic identification.

We didn’t know much about Sredni Stog or Corded Ware, and we still don’t. I can’t see the future, and I don’t have access to information from Reich-Jena or Copenhagen groups, and never have. But I just don’t see the need to explain Corded Ware as derived from (coeval) Early Yamna, and I haven’t since the 2015 papers. It was not the best explanation for the data that was published, and the more information we receive, the less sense this theory makes.

However, I guess we will see some groups still resorting to the good old Yamnaya ancestral component™ = Indo-European no matter what, consciously ignoring that a proportion of ancestral components (some combination of EHG:CHG:WHG in this case) means nothing without a proper explanation of their precise temporal and regional origin, and how they connect with Yamna; just like the CHG ancestry = Indo-European trend we are living right now does not make any sense.

Publishing only selected results after trying every possible combination of samples with bioinformatic tools does not help strengthen this connection, either.

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