Stone Age plague accompanying migrants from the steppe, probably Yamna, Balkan EBA, and Bell Beaker, not Corded Ware

copper-age-late-bell-beaker

In the latest revisions of the Indo-European demic diffusion model, using the results from the article Early Divergent Strains of Yersinia pestis in Eurasia 5,000 Years Ago, by Rasmussen et al., Cell (2015), I stated (more or less indirectly) that the high east-west mobility of the Corded Ware migrants across related cultures might have been responsible for the spread of this disease, which seems to have been originally expanded from Central Eurasia.

New results appeared recently in the article The Stone Age Plague and Its Persistence in Eurasia, by Valtueña et al., Current Biology (2017), which may contradict that interpretation.

corded-ware-map
Diachronic map of Copper Age migrations ca. 3100-2600 BC – Corded Ware

Abstract:

Yersinia pestis, the etiologic agent of plague, is a bacterium associated with wild rodents and their fleas. Historically it was responsible for three pandemics: the Plague of Justinian in the 6th century AD, which persisted until the 8th century [ 1 ]; the renowned Black Death of the 14th century [ 2, 3 ], with recurrent outbreaks until the 18th century [ 4 ]; and the most recent 19th century pandemic, in which Y. pestis spread worldwide [ 5 ] and became endemic in several regions [ 6 ]. The discovery of molecular signatures of Y. pestis in prehistoric Eurasian individuals and two genomes from Southern Siberia suggest that Y. pestis caused some form of disease in humans prior to the first historically documented pandemic [ 7 ]. Here, we present six new European Y. pestis genomes spanning the Late Neolithic to the Bronze Age (LNBA; 4,800 to 3,700 calibrated years before present). This time period is characterized by major transformative cultural and social changes that led to cross-European networks of contact and exchange [ 8, 9 ]. We show that all known LNBA strains form a single putatively extinct clade in the Y. pestis phylogeny. Interpreting our data within the context of recent ancient human genomic evidence that suggests an increase in human mobility during the LNBA, we propose a possible scenario for the early spread of Y. pestis: the pathogen may have entered Europe from Central Eurasia following an expansion of people from the steppe, persisted within Europe until the mid-Bronze Age, and moved back toward Central Eurasia in parallel with human populations.

plague_phylogeny_eurasia
Maximum-Likelihood Tree and Percent Coverage Plot of Virulence Factors of Yersinia pestis. (A) Maximum-likelihood tree of all Yersinia pestis genomes, including 1,265 SNP positions with complete deletion. Nodes with support R95% are marked with an asterisk. The colors represent different branches in the Y. pestis phylogeny: branch 0 (black), branch 1 (red), branch 2 (green), branch 3 (blue), branch 4 (orange), and LNBA Y. pestis branch (purple). Y. pseudotuberculosis-specific SNPs were excluded from the tree for clarity of representation. In the light-colored boxes, discussed losses and gains of genomic regions and genes are indicated. Related

It seems that, notwithstanding the simplistic (white) arrows of steppe ancestry expansion shown in their map (see below), the actual expansion of Yersinia pestis might have in fact accompanied Yamna migrants from the Pontic-Caspian steppe into Early Bronze Age cultures from the Balkans, including Bell Beaker migrants, as the phylogenetic analysis and dates suggest – and as the potential arrows of the plague expansion in the map (in green) show.

Late Corded Ware migrants would have only later expanded the disease to eastern Europe, as shown in the second map, most likely because of their close contact with Bell Beaker migrants (but remaining culturally distinct from them), and indeed because of the mobility accross related Corded Ware cultures up to the Urals.

The cultural-historical community in the Late Neolithic between steppe peoples that would evolve into Uralic-speaking Sredni Stog/Corded Ware migrants in the western steppe, and Late Indo-European-speaking Yamna/SE EBA/Bell Beaker migrants originally from the eastern steppe, would allow for the spread of the disease first among steppe groups, and then from both distinct late groups into their respective expanded regions.

The phylogenetic tree of Y. pestis available right now (see above), however, seems to suggest a stronger initial link to Yamna migrants, i.e. an origin in the North Caspian steppe, and an expansion with Yamna into the north Pontic area, into the Caucasus, and with the Afansevo culture, spreading later with Balkan EBA cultures and the expansion of Bell Beaker peoples.

Instead of warring nature, close ties, and mobility of Corded Ware peoples (reasons I used to justify the rapid spread of the disease among CWC groups), I guess it was rather the higher population density of SE Europe compared to the regions north of the loess belt, as well as the greater admixture of Yamna migrants with native SE European populations, the factors which might have helped expand the disease.

plague-expansion-europe
Map of Proposed Yersinia pestis Circulation throughout Eurasia (A) Entrance of Y. pestis into Europe from Central Eurasia with the expansion of Yamnaya pastoralists around 4,800 years ago. (B) Circulation of Y. pestis to Southern Siberia from Europe. Only complete genomes are shown.

Nevertheless, lacking more data, it is unclear if the disease expanded with both steppe groups.

Related:

Globular Amphora not linked to Pontic steppe migrants – more data against Kristiansen’s Kurgan model of Indo-European expansion

eneolithic-steppe-cultures

New open access article, Genome diversity in the Neolithic Globular Amphorae culture and the spread of Indo-European languages, by Tassi et al. (2017).

Abstract:

It is unclear whether Indo-European languages in Europe spread from the Pontic steppes in the late Neolithic, or from Anatolia in the Early Neolithic. Under the former hypothesis, people of the Globular Amphorae culture (GAC) would be descended from Eastern ancestors, likely representing the Yamnaya culture. However, nuclear (six individuals typed for 597 573 SNPs) and mitochondrial (11 complete sequences) DNA from the GAC appear closer to those of earlier Neolithic groups than to the DNA of all other populations related to the Pontic steppe migration. Explicit comparisons of alternative demographic models via approximate Bayesian computation confirmed this pattern. These results are not in contrast to Late Neolithic gene flow from the Pontic steppes into Central Europe. However, they add nuance to this model, showing that the eastern affinities of the GAC in the archaeological record reflect cultural influences from other groups from the East, rather than the movement of people.

globular-amphora-pca-admixture
(a) Principal component analysis on genomic diversity in ancient and modern individuals. (b) K = 3,4 ADMIXTURE analysis based only on ancient variation. (a) Principal component analysis of 777 modern West Eurasian samples with 199 ancient samples. Only transversions considered in the PCA (to avoid confounding effects of post-mortem damage). We represented modern individuals as grey dots, and used coloured and labelled symbols to represent the ancient individuals. (b) Admixture plots at K = 3 and K = 4 of the analysis conducted only considering the ancient individuals. The full plot is shown in electronic supplementary material, figure S7. The ancient populations are sorted by a temporal scale from Pleistocene to Iron Age. The GAC samples of this study are displayed in the box on the right.

Excerpt, from the discussion:

In its classical formulation, the Kurgan hypothesis, i.e. a late Neolithic spread of proto-Indo-European languages from the Pontic steppes, regards the GAC people as largely descended from Late Neolithic ancestors from the East, most likely representing the Yamna culture; these populations then continued their Westward movement, giving rise to the later Corded Ware and Bell Beaker cultures. Gimbutas [23] suggested that the spread of Indo-European languages involved conflict, with eastern populations spreading their languages and customs to previously established European groups, which implies some degree of demographic change in the areas affected by the process. The genomic variation observed in GAC individuals from Kierzkowo, Poland, does not seem to agree with this view. Indeed, at the nuclear level, the GAC people show minor genetic affinities with the other populations related with the Kurgan Hypothesis, including the Yamna. On the contrary, they are similar to Early-Middle Neolithic populations, even geographically distant ones, from Iberia or Sweden. As already found for other Late Neolithic populations [18], in the GAC people’s genome there is a component related to those of much earlier hunting-gathering communities, probably a sign of admixture with them. At the nuclear level, there is a recognizable genealogical continuity from Yamna to Corded Ware. However, the view that the GAC people represented an intermediate phase in this large-scale migration finds no support in bi-dimensional representations of genome diversity (PCA and MDS), ADMIXTURE graphs, or in the set of estimated f3-statistics.

globular-amphora-hunter-gatherer-farmer-yamnaya
Scheme summarizing the five alternative models compared via ABC random forest. We generated by coalescent simulation mtDNA sequences under five models, differing as to the number of migration events considered. The coloured lines represent the ancient samples included in the analysis, namely Unetice (yellow line), Bell Beaker (purple line), Corded Ware (green line) and Globular Amphorae (red line) from Central Europe, Yamnaya (light blue line) and Srubnaya (brown line) from Eastern Europe. The arrows refer to the three waves of migration tested. Model NOMIG was the simplest one, in which the six populations did not have any genetic exchanges; models MIG1, MIG2 and MIG1, 2 differed from NOMIG in that they included the migration events number 1, 2 (from Eastern to Central Europe, respectively before and after the onset of the GAC), or both. Model MIG2, 3 represents a modification of MIG2 model also including a back migration from Central to Eastern Europe after the development of the Corded Ware culture.

Together with Globular Amphora culture samples from Mathieson et al. (2017), this suggests that Kristiansen’s Indo-European Corded Ware Theory is wrong, even in its latest revised models of 2017.

gimbutas-kurgan-indo-european
The background shading indicates the tree migratory waves proposed by Marija Gimbutas, and personally
checked by her in 1995. The symbols refer to the ancient populations considered in the ABC analysis

On the other hand, the article’s genetic finds have some interesting connections in terms of mtDNA phylogeography, but without a proper archaeological model it is difficult to explain them.

mtdna-yamnaya-gac-corded-ware-bell-beaker
Haplogroup frequencies were obtained for Early Neolithic (EN), Middle Neolithic (MN), Chalcolithic (CA), and Late Neolithic (LN). The color assigned to each haplogroup is represented on the lower right part of each plot. Haplogroup frequencies were plotted geographically using QGIS v2.14.

Text and images from the article under Creative Commons Attribution 4.0 license.

Discovered first via Bernard Sécher’s blog.

See also:

Correlation does not mean causation: the damage of the ‘Yamnaya ancestral component’, and the ‘Future American’ hypothesis

america-languages-lowlandic

Human ancestry can only help solve anthropological questions by using all anthropological disciplines involved. I have said that many times in this blog.

Correlation does not mean causation

Really, it does not.

You might think the tenet ‘correlation does not mean causation‘ must be evident at this point in Statistics, and it must also be for all those using statistical methods in their research. But it is sadly not so. A lot of researchers just look for correlation, and derive conclusions – without even an initial sound hypothesis to be contrasted… You can judge for yourself, e.g. reading the many instances of this complaint in recent publications of Biomedical and Social Sciences, on the interesting blog Statistical Modeling, Causal Inference, and Social Science.

In anthropological questions regarding Indo-European studies there is an added handicap: not taking correlation to mean causation does also mean – to avoid at least the most obvious confounders – taking into account the multiple linguistic and archaeological data that are available right now, to explain the expansion of Indo-European languages.

You might also believe that international researchers in Human Evolutionary Biology – after all, this is essentially a biomedical discipline – are acquainted with statistical methods and their problems when applied to their field. And that scientific journals – and especially those with the highest impact factors, like Nature, Science, or PNAS – have professional, careful reviewers who would never accept papers that equal correlation with causation, especially when Social Sciences are involved (because this alone might make errors grow exponentially…). Sadly, this is obviously not so, either.

https://imgs.xkcd.com/comics/correlation.png

The ‘Yamnaya component’ concept and its damage

From Allentoft et al. (2015), emphasis is mine:

Both studies [Haak et al. (2015) and this one] found a genetic affinity between samples from a central European culture known as Corded Ware, which existed from around 2500 bc, and samples from the earlier Yamnaya steppe culture. This similarity between distant populations is best explained by a substantial westward expansion of the Yamnaya or their close relatives into central Europe (Fig. 1b). Such an expansion is consistent with the steppe hypothesis, which argues that Corded Ware cultures were a conduit for the dispersal of Indo-European languages into Europe.

More interesting than these vague words – and the short, almost invisible suggestion that Yamna may not be exactly the population behind Corded Ware peoples – are the maps that illustrated in Nature their risky hypothesis: they called it “steppe hypothesis“, like that (in general terms), as if everyone defending a steppe origin for Proto-Indo-European would support such a model, when they actually referred to the specific hypothesis of one of their authors (Kristiansen), one of the few archaeologists who keep Gimbutas’ concept of the ‘Kurgan peoples’ alive, based on the Corded Ware culture:

Allentoft Corded Ware
Allentoft et al. (2015): “They conclude that the Corded Ware culture of central Europe had ancestry from the Yamnaya. Allentoft et al. also show that the Afanasievo culture to the east is related to the Yamnaya, and that the Sintashta and Andronovo cultures had ancestry from the Corded Ware. Arrows indicate migrations — those from the Corded Ware reflect the evidence that people of this archaeological culture (or their relatives) were responsible for the spreading of Indo-European languages. All coloured boundaries are approximate.”

In many publications that followed, the trend has been to reproduce this graphical model, by asserting (or implying) that Bell Beaker peoples were the result of subsequent Corded Ware migrations, and indeed that Corded Ware peoples migrated from the Yamna culture, and were thus the vector of expansion for Indo-European languages in Europe.

All of this is being proven wrong, as I predicted: see Mathieson et al. (2017) and Olalde et al. (2017) for recently studied samples with ‘steppe component’, older than (and unrelated to) the Yamna culture. However, no retraction (or correction, whatever) has been published to date about the concept of the ‘Yamnaya ancestry expansion’, and its consequences.

We shall see then just a rather surreptitious shift in terminology from ‘Yamnaya’ to ‘steppe’ component, to adapt to the new data – i.e. some damage control while the ship of ‘Yamnaya ancestry’ capsizes – but little else. “Earlier ‘Yamnaya ancestry’, you say? Just, you know, let’s call it ‘steppe ancestry’ and shift the expansion of Indo-European languages to one or two thousand years earlier, and done!”

The damage of this post-truth genetics is already done: we will see the unending distribution on the Internet in general, and on social networks in particular, of these grandiose conclusions, of far-fetched Indo-European migration models that include the Corded Ware culture, of simplistic maps with apparently harmless ‘arrows of migration’ (like the above) representing fictional population movements suggesting nonexistent dialectal branches.

You might be one of those sceptics wary of so many boring statistical rules: “But it’s a safe reasoning: Yamanaya samples have an ‘ancestral component’ that is found elevated in Corded Ware samples, and less so in Bell Beaker samples, and PCA showed a similar result…so the migration model Yamnaya -> Corded Ware -> Bell Beaker is a priori correct, right?”

The ‘Future American’ hypothesis

Let me illustrate this attractive “Correlation = Causation” argument, using it to solve the problem of Future American languages.

Suppose we live in a future post-apocalyptic world ca. 3500 AD, with no surviving historical records before 3000 AD. None. Just investigation of cultures and their relationship by Archaeology, proto-languages reconstructed and language families identified by Linguistics, etc.

We have thus Future Germanic and Future Romance as the only language families spoken in Future Western Europe and in the Future Americas, in a distribution similar to the present day*, and we have certain somehow related archaeologically-defined cultures on both sides of the Atlantic, like Briton, Iberian, Norman, or Lowlandish, although their distribution remains partly undefined in time and space.

* If you are really curious about this scenario, you can read about the potential evolution of a Future North-American language.

But what languages did the ancestors of Future Americans speak, and who spread them? That question remains far from being settled by our future researchers, in spite of the solidest linguistic and migration models (talking mainly about Briton and Iberian cultures): too many authorities out there questioning them, fighting to impose their own pet theories.

Suddenly, the newly developed field of Human Ancestry comes to save the day. So let’s say we have this map of ancient samples recovered (dated from, say, the 6th to the 18th century AD), and our study is centered on the newly described “Western European” component (a precise combination of, say, WHG+steppe), which peaks in early samples from the Low Lands – hence we call it, quite daringly, “Lowlandic component“.

Our group is keen to demonstrate that the ancient Lowlandic culture described in Archaeology (marked especially by the worldwide distribution of tulips among other traits) is the origin of Western European and American languages… Now, let’s reach conclusions about migrations in the Middle Ages!

america-languages-lowlandic
‘Future American’ hypothesis. Migration routes in Western Europe and the Americas during the Middle Ages, based on the ‘Lowlandic component’ (Click to open higher quality version).

PCA shows that South-West European samples cluster closely to some North-West European samples, and that some late South American samples available cluster at some distance from North American samples – nearer to a native component represented by two individuals with 0% Lowlandic ancestry and a different cluster in PCA. And some North-American samples cluster quite closely to North-West European samples.

Based on the decrease in ‘Lowlandic component’ in the different samples and on PCA, we conclude that Lowlandic peoples (“or their close relatives”) must have migrated at the same time to North America, South America (or potentially from North America to South America?) as well as western, central, and northern Europe. Both migration events must have happened roughly at the same time, in part because both distinct language families appear in a north-south distribution, and Proto-Lowlandic must be (according to Genetics) the ancestor of both, Proto-Future-Germanic and Proto-Future-Romance.

That makes a lot of sense! A huge Lowlandic pressure for migration, you see. Push-pull mechanisms and stuff. A Lowlandic Empire probably (scattered remains are found everywhere)! And, judging by the presence of the ‘Lowlandic component’ in Future East Europe from the Elbe to the Vistula, maybe Lowlandic peoples spread Proto-Slavic, too! We can even date the common Lowlandic-Slavic proto-language this way! So many groundbreaking conclusions!

Future scholars supporting the Lowlandic homeland are on fire; they can’t get enough of publishing papers on the subject. “Two different Future American language families with cultural origins in Britain and Iberia, my ass! Because genetics.”

And don’t forget the future people of haplogroup R1b-U106 and high Lowlandic component: Wow, they are the heirs of those who expanded Future Germanic and Future Romance languages everywhere, aren’t they? How proud they must be. And who wouldn’t want to have these tall, blond, blue-eyed Lowlanders as their forefathers? Personalised genetic analysis is selling like crazy: “let’s know our Lowlandic percentage!”. Everyone is happy, colourful maps with lots of arrows and shit…

But – your future you might ask in awe, seeing that this doesn’t sound quite right, based on your basic archaeological and linguistic knowledge:

  • What about specific models of migration proposed to date? The solidest ones, not just anyone that seems to fit?
  • What about the dialectal classification of languages? The mainstream ones, not those that are compatible with this interpretation?
  • What about archaeological cultures to which individual samples belonged?
  • What about the actual dates of each sample? And how this date relates to the state of the culture to which it belongs?
  • What about the haplogroups, and the actual subclade of each haplogroup?
  • What about the territories, cultures, and dates not sampled, could they change this interpretation in light of known archaeological models?
  • And what about the actual origin of that ancestral component they so frivolously named? Dit it really appear ex nihilo in the Low Lands, and expanded from it?

“Who cares! This new data is sooo coool… And it proves what we wanted, what a coincidence! And it’s numbers, mate! Numbers don’t lie.”

 
No, numbers don’t lie. But people do.

Correlation is fun, isn’t it?

 

Related:

New Ukraine Eneolithic sample from late Sredni Stog, near homeland of the Corded Ware culture

eneolithic-europe

Just one day after publishing the draft of the Indo-European demic diffusion model, 3rd version, Mathieson et al. (2017) have updated some information in a new version of their article, including a new interesting sample from late Sredni Stog. It gives support to what I predicted, regarding the potential origin of the third Corded Ware horizon.

After my first version, findings in Olalde et al. (2017) and Mathieson et al. (2017) supported some of my predictions. Now after my third, their new data also supports another prediction. Because the model is based on solid linguistic and archaeological models. Here is an excerpt from the Indo-European demic diffusion model, 3rd ed. (pp. 55-56):

At the end of the Trypillian culture, herding/hunting trends intensified, and the agricultural system collapsed, with people moving to the steppe zone, as confirmed by the presence of numerous graves to the south (Rassamakin 1999). At the same time, the Trypillian world absorbed a foreign tradition related to materials of settlement sites of the Dnieper steppes – such as the late Sredni Stog culture –, like cord impressions and burial rites similar to the later Corded Ware culture, marking also the transformation of decors and changes in their interpretation (Palaguta 2007).

The similarity in burial rituals between Yamna and Corded Ware made Gimbutas define a common “Kurgan people”, whose relationship has also been long supported by Kristiansen (Kristiansen 1989; Kristiansen et al. 2017). An equivalence of both burial rites has been, however, rejected (Häusler 1963, 1978, 1983), and it is generally agreed that the Yamna culture did not expand to the north of the Tisza River.

The importance of horse exploitation in Deriivka, in the forest-steppe zone of the north Pontic region along the Dnieper region, during the Middle Eneolithic period (probably ca. 3700-3530 BC), suggests that horses played a significant role in the life of this Sredni Stog community (Anthony and Brown 2003). In its late period (ca. 4000-3500 BC), this culture had adopted corded ware pottery, and stone battle-axes.

However, this [sic] western steppe peoples were mainly hunters (Rassamakin 1999), and the ‘herding skill’ essential for wild horse domestication seems absent (Kuzmina 2003). All this has been confirmed with zooarchaeological evidence and new molecular and stable isotope results, suggesting an absence of horse domestication in territories of the late Sredni Stog culture in the north Pontic steppe (Mileto et al. 2017), before the advent of migrants from the Indo-European-speaking Repin culture.

The new sample described in Mathieson et al. (2017), dated ca. 4200 BC (but within a wide range, 5000-3500 BC) is from a site classified as of late Sredni Stog (although potentially from Post-Mariupol / Kvitjana), a culture of hunters who probably did not breed domesticated horses (even after the period of conquest and dominance of Suvorovo-Novodanilovka chiefs, from Indo-Hittite-speaking early Khvalynsk, who had domesticated horses), and – more importantly – is of R1a-M417 lineage, shows high so-called “Yamna component” in ADMIXTURE, and clusters among Corded Ware samples in PCA approximately a thousand years before this culture’s expansion. Information from the supplementary material:

An Eneolithic cemetery of the Sredny Stog II culture was excavated by D. Telegin in 1955-1957 near the village of Alexandria, Kupyansk district, Kharkov region on the left bank of the river Oskol. A total of 33 individuals were recovered. Based on craniometric analysis (I.Potekhina 1999) it was suggested that the Eneolithic inhabitants of Alexandria were not homogeneous and resulted from admixture of local Neolithic hunter-gatherers and early farmers, possibly Trypillian groups. We report genetic data from one individual: I6561

pca-mathieson_ukraine_eneolithic
PCA, Admixture of Ukraine Eneolithic and other samples from Mathieson et al. (2017)

Another individual from Eneolithic Ukraine (of R1b1 xM269 lineage) clusters quite closely with Neolithic samples from the Baltic, which points to the strong connection between both – southern and northern – regions of east-central Europe before the period of great Chalcolithic expansions, and the potential origin of the spread of R1b (xM269) lineages with the Corded Ware culture.

The so-called ‘Yamna component’ – an infamous name which, as expected, is turning out to be very wrong – has been found quite elevated in this sample, previous and completely unrelated to the Yamna culture and its expansion, and similar to the (later) Corded Ware samples. In fact, we are seeing that Corded Ware samples are actually clustering closely with east-central Europe (excluding the CWC outlier), and not with Yamna and other Indo-European-speaking steppe cultures.

pca-mathieson2-ukraine-eneolithic
‘Yamna component’ (in yellow) in the North-West Pontic Steppe and the Balkans, including Eneolithic Ukraine samples

It will be fun to see the mess that certain researchers have made (and will still make in the near future) of their findings coupled with the concept of “Yamna component”, when trying to describe the “proxy ancestral populations” of European Copper Age and Bronze Age cultures… Difficult times ahead for many, after the collapse of the simplistic Yamna -> Corded Ware -> Bell Beaker genetic model laid out since Haak et al. (2015) and Allentoft et al. (2015).

[EDIT 27 September 2017] Not directly related, but here is today’s interesting discussion on Twitter surrounding the ancestral populations of the “Yamnaya component”, for illustration of the discussions to come when this ancestry is divided into different, more precise, older (Neolithic) steppe components, and these in turn shown to contribute to different European and Asian Chalcolithic and Bronze Age cultures:

Given the variance found in the three samples from Eneolithic Ukraine (comparable to the variance found in east Bell Beaker samples), we may now be getting closer to the precise territory and culture where the Corded Ware culture might have formed, which cannot be much further from the Dnieper-Dniester region before the Yamna expansion to the west ca. 3300 BC, judging from the elevated steppe component.

It seems, because of the proximity of both cultures and the similar dates of their migrations, that the westward expansion of the Yamna culture may have indeed provided an important push (among some strong ‘pull’ forces) for peoples of the expansion of the Corded Ware culture.

eneolithic_Caucasus
Diachronic map of Eneolithic migrations in the Caucasus ca. 4000-3100 BC

It keeps being demonstrated that archaeologists like Anthony, Heyd, Mallory, etc. were right where others tried to interpret admixture based on few samples and their own imagination, without any knowledge (or interest) whatsoever about Archaeology or Linguistics.

So Genetics reinforces the solidest models of Archaeology and Linguistics? Professional academics being mostly right in their careful research, and amateur geneticists playing with software being wrong? Who would have thought… More and more papers help thus shut up naysayers who state (again and again) that new algorithms are here to revolutionise these academic fields.

As Heyd predicted more than 10 years ago, and as many pointed out in terms of linguistic influence (like Mallory or Prescott) the transformation of Yamna settlers into the east Bell Beaker culture, and this culture‘s spread into western and northern Europe, must be noticed in genetic investigation.

The expansion of peoples is known to be associated with the spread of a certain admixture component + the expansion and reduction in variability of a haplogroup (i.e. few male lineages are usually more successful during the expansion): Neolithic farmers from the Middle East expanding with haplogroup G2a; Natufian component (Levant hunter-gatherers or later, Neolithic farmers) and haplogroup E southward into Africa; CHG component expansion with haplogroup J; WHG expansion into east Europe with haplogroup R1b; etc.

There were (at least) two main expansion processes involving Proto-Indo-European: one causing the branching off of the language ancestral to Anatolian, and another during the spread of Late Indo-European dialects. Based on this, and on known archaeological models, I have predicted since the first version of the demic diffusion model:

  • Based on haplogroups found until then in Yamna (R1b-M269), Corded Ware (R1a-M417, especially Z645), and Bell Beaker (R1b-L151):
    • that mainly R1b-L23 (especially L51) lineages and more steppe admixture would be found in east Bell Beaker – confirmed some two months after my publication by Olalde et al. (2017);
    • and that mainly R1a-M417 (especially Z645) subclades will be found in Corded Ware samples.
  • Based on the finding of “Yamna component” in the Corded Ware culture: that this admixture must have come from somewhere else. I pointed out to eastern Europe, including the forest and forest-steppe zone especially in the natural continuum of the Dniester-Dnieper region. Especially after Mathieson et al. (2017), in my second and third versions of the model, I have more specifically suggested a southern origin in the region, nearer to where the CHG ancestry must have come from (the Caucasus and cultures formed in contact with it), according to mainstream archaeological data, i.e. cultures of the North Pontic steppe / steppe-forest. But of course, until more samples are available, more CHG ancestry in other cultures of the Forest Zone cannot be discarded.

For the vast majority of academics, more samples (regionally proportioned) are needed only from early Corded Ware, as we have from Bell Beaker: if they are (as expected) mostly R1a-M417, then everything is clear, and it will finally mean the end for the tiring, now almost ‘traditional’ association R1a – Proto-Indo-European. Some more samples from the potential homeland of the third Corded Ware horizon, most likely Ukraine (Podolia and Volynia regions), nearer to the time of the Corded Ware expansion, would also be great, to locate the actual ancestral population of Corded Ware migrants – recognisable by the main presence of haplogroup R1a-Z645 (formed ca. 3500 BC), and elevated “Yamna component” before the arrival of the Yamna culture…

If, however, early Corded Ware samples of R1b-L23 subclades are found in certain quantity, especially old samples from east-central Europe (excluding Yamna migrants along the Prut), the tricky question of Late Indo-European cultural diffusion will remain: Did Corded Ware peoples adopt a Late Indo-European language from clans of R1b-L23 lineages? That is what Kristiansen and Anthony have been betting for, a cultural diffusion, caused by:

  • A long-lasting contact, according to Kristiansen (1989,…,2017). He defends that Sredni Stog adopted the language – but obviously not the same culture – from the east, but that it is a genetic and cultural mix from Globular Amphora, Trypillia, and steppe cultures. This has been Kristiansen’s model for almost 30 years, and it follows Marija Gimbutas’ outdated theory of the “Kurgan people”.
  • A rapid change according to Anthony (2007). He associates the adoption of Pre-Germanic with the domination of Yamna chiefs over Usatovo people, and the adoption of Balto-Slavic by the people from (Corded Ware) Middle Dnieper group because of the technical superiority of neighbouring Yamna herders.

Linguistics, with the growing support of a North-West Indo-European group, points clearly to a European expansion of a community speaking the ancestral language of Italo-Celtic, Germanic, and probably Balto-Slavic. Archaeology, too, showed migration from Yamna only to south-eastern Europe (correcting Gimbutas’ Kurgan model) and later with east Bell Beaker mainly into central, western, and northern Europe.

Even Kristiansen admits that only after the arrival of Bell Beaker in Scandinavia was a linguistic community (i.e. Germanic) formed – although he places the center of gravity in Úněticean influence, and (yet again) a cultural diffusion event into the Danish Dagger period.

Because of more and more data contrasting with old theories, some have elected to develop weak, indemonstrable links, to keep supporting e.g. Gimbutas’ concept of “Kurgan people” in Archaeology, and a sudden, early expansion of all PIE dialects at once in Linguistics. It seems that, after so much fuss about the (misleading) ‘Yamna component’ concept – and so many far-fetched assumptions by amateur geneticists -, the Corded Ware connection will once again hinge on weak, indemonstrable cultural diffusion theories, be it ‘Kurgan peoples’ (including now, of course, Eneolithic cultures of Ukraine) or any culture from eastern Europe that will reveal some close samples to Corded Ware migrants, in terms of PCA, ADMIXTURE, or haplogroup.

So once we find mainly R1a-Z645 in more Corded Ware samples (and this haplogroup and more “Yamna component” in non-Yamna cultures of Eneolithic Ukraine, and potentially Poland or Belarus) we all may finally expect a peaceful acceptance of reality, at least in Genetics? Nope. No siree. Nein. Not then, not ever.

Why? Because some people want their paternal lineage to have lived in their historical region, and spoken their historical language, since time immemorial. It won’t matter if Archaeology, Linguistics, Genetics, etc. don’t support their claims: if they need to use some aspects of admixture, or haplogroups (or a combination of them) from carefully selected samples instead of looking at the whole picture; if they have to support that Indo-Europeans came from a culture different than Yamna, in- or outside of the steppe or forest-steppe, be it the Balkans, Anatolia, Armenia, or the Moon; if their proto-language should then come directly from Indo-Hittite, or from a Germano-Slavonic, or Indo-Slavonic, or Indo-Germanic group, or whatever invented dialectal branch necessary to fit their model, or if they have to support the ‘constellation analogy’ of Clackson, or thousands of years of development for each branch; etc. They will support whatever is necessary.

And this adaptation, obviously, has no end. It’s stupid, I know. But that’s how we are, how we think. We have seen that these sad trends continue no matter what, for decades, and not only regarding Indo-European. Some common examples include:

  • Indo-Aryan-speaking Indians defending an autochthonous origin of R1a and Indo-European; as well as the ‘opposite’ autochtonous continuity theory of Dravidian-speaking Indians (based on ASI ancestry, haplogroup R2, mtDNA haplogroup M, or whatever is at hand).
  • Western Europeans defending an autochthonous origin of the R1b haplogroup, with a Palaeolithic or Mesolithic origin, including the language, viz. the recent Indo-European from the Atlantic façade theories (in the Celtic from the West series, by Koch and Cunliffe); the now fading Palaeolithic Continuity Theory; and many other forgotten Eurocentric proposals; as well as the more recent informal hints of a central European/Balkan homeland based on the Villabruna cluster and south-eastern Mesolithic finds, which is at risk of being related to a Balkan origin of Proto-Indo-European
    • There is also the ‘opposite’ theory of the autochthonous origin of the Basques, including Proto-Iberians and potentially other peoples like Paleo-Sardinians, based on the previously popular Vasconic-Uralic hypothesis (and an ancient Europe divided into R1b and N1c1 haplogroups), which is still widely believed in certain regions.
  • Finno-Ugric speakers of N1c1 lineage defending an autochtonous origin of the lineage and language in eastern Europe.
  • Nordic speakers supporting the autochthonous nature of Germanic and haplogroup I1 to Scandinavia.
  • Armenian speakers delighted to see a proposal of Indo-European homeland in the Armenian highlands, be it supported by glottalic consonants, CHG ancestrty, R1b (xM269) or J lineages…
  • Greek speakers now willing to support continuity of haplogroup J as a ‘native’ Greek lineage, of people speaking Proto-Greek (and in earlier times PIE), because of two Minoan, and one Mycenaean samples found in Lazaridis et al. (2017).
  • Even Turks linking Yamna with the expansion of Turkic languages. That one is fun to read, almost like a parody for the rest – substituting “Indo-European” for “Turkic”.
  • For years, a lot of people – me included (at least since 2005) – believed, because of modern maps of R1a distribution, that R1a and Corded Ware are the vector of Indo-European languages. For those of us who don’t have any personal or national tie with this haplogroup, this notion has been easy to change with new data. For others, it obviously isn’t, and it won’t be.
R1a_distribution_Eurasia
Modern R1a distribution in Eurasia (Wikipedia, 2008). The typical, simplistic map we relied on in the 2000s to derive wrong conclusions based on Genetics, conclusions which are sadly still alive and kicking…

For all these people, a sample, result, or conclusion from any paper, just dubiously in favour, means everything, but a thousand against mean nothing, or can be reinterpreted to support their fantasies.

The Kossinnian autochthonous continuity” crap permeates this relatively new subfield of Human Evolutionary Genetics, as it permeated Indo-European studies (first Linguistics, then Archaeology) in its infancy. It seems to be a generalised human trend, no doubt related to some absurd inferiority complex, mixed with historical romanticism, a certain degree of chauvinism, and (falling in the eternal Godwin’s Law of our field) some outdated, childish notion of ‘supremacy’ linked with the expansion of the own language and people.

Such simplistic and popular models are also lucrative, judging by the boom in demand for DNA analysis, which companies embellish with modern fortune tellers (or fortune tellers themselves sell for a price), promising to ascertain your ‘ancestry proportions’ using automated algorithms, so that you don’t have to get lost in complex genetic data and prehistoric accounts, which can’t help you define your “ethnicity”…

Some just don’t want to realize that the spread of prehistoric languages (like Late Indo-European dialects) was a complex, non-uniform, stepped process, devoid of modern romantic concepts, which in genetic terms necessarily included later founder effects and cultural diffusions, so that no one can trace their haplogroup, lineage, family, region, or country to any single culture, language, or ethnic group. The same, by the way, can be said of peoples and countries in historic times.

As I said before, we shall expect supporters of the Kurgan model (and thus the expansion of R1a-Z645 with Yamna) to wait for just one sample of R1a-M417 in Yamna and/or Bell Beaker (which will eventually be found), and just one sample of R1b-M269 in Corded Ware (which will also eventually be found), to blow the horn of victory in this naïve competition against time, general knowledge, and (essentially) themselves.

A sad consequence of how we are is that, because of the obvious influence of these stupid modern ethnolinguistic agendas, because we are not all rowing in the same direction, genetic results and conclusions are still perceived as far-fetched and labile, and thus most archaeologists and linguists prefer not to include genetic results in their investigation. And those who dare to do so, are badly counselled by those who go with the tide, so that their papers become almost instantly outdated.

Related:

Indo-European demic diffusion model, 3rd edition

pca-yamna-corded-ware

I have just uploaded the working draft of the third version of the Indo-European demic diffusion model. Unlike the previous two versions, which were published as essays (fully developed papers), this new version adds more information on human admixture, and probably needs important corrections before a definitive edition can be published.

The third version is available right now on ResearchGate and Academia.edu. I will post the PDF at Academia Prisca, as soon as possible:

pca-map-yamna-corded-ware-bell-beaker
Map overlaid by PCA including Yamna, Corded Ware, Bell Beaker, and other samples

Feel free to comment on the paper here, or (preferably) in our forum.

A working version (needing some corrections) divided by sections, illustrated with up-to-date, high resolution maps, can be found (as always) at the official collaborative Wiki website indo-european.info.

Something is very wrong with models based on the so-called ‘steppe admixture’ – and archaeologists are catching up

steppe-admixture

Russian archaeologist Leo Klejn has published an article Discussion: Are the Origins of Indo-European Languages Explained by the Migration of the Yamnaya Culture to the West?, which includes the criticism received from Wolfgang Haak, Iosif Lazaridis, Nick Patterson, and David Reich (mainly on the genetic aspect), and from Kristian Kristiansen, Karl-Göran Sjögren, Morten Allentoft, Martin Sikora, and Eske Willerslev (mainly on the archaeological aspect).

I will not post details of Klejn’s model of North-South Proto-Indo-European expansion – which is explained in the article, and relies on the north-south cline of ‘steppe admixture’ in the modern European population -, since it is based on marginal anthropological methods and theories, including glottochronological dates, and archaeological theories from the Russian school (mainly Zalyzniak), which are obviously not mainstream in the field of Indo-European Studies, and (paradoxically) on the modern distribution of ‘steppe admixture’…

The most interesting aspects of the article are the reactions to the criticism, some of which can be used from the point of view of the Indo-European demic diffusion model, too. It is sad, however, that they didn’t choose to answer earlier to Heyd’s criticism (or to Heyd’s model, which is essentially also that of Mallory and Anthony), instead of just waiting for proponents of the least interesting models to react…

The answer by Haak et al.:

Klejn mischaracterizes our paper as claiming that practitioners of the Corded Ware culture spoke a language ancestral to all European Indo-European languages, including Greek and Celtic. This is incorrect: we never claim that the ancestor of Greek is the language spoken by people of the Corded Ware culture. In fact, we explicitly state that the expansion of steppe ancestry might account for only a subset of Indo-European languages in Europe. Klejn asserts that ‘a source in the north’ is a better candidate for the new ancestry manifested in the Corded Ware than the Yamnaya. While it is indeed the case that the present-day people with the greatest affinity to the Corded Ware are distributed in north-eastern Europe, a major part of the new ancestry of the Corded Ware derives from a population most closely related to Armenians (Haak et al., 2015) and hunter-gatherers from the Caucasus (Jones et al., 2015). This ancestry has not been detected in any European huntergatherers analysed to date (Lazaridis et al., 2014; Skoglund et al., 2014; Haak et al., 2015; Fu et al., 2016), but made up some fifty per cent of the ancestry of the Yamnaya. The fact that the Corded Ware traced some of its ancestry to the southern Caucasus makes a source in the north less parsimonious.

In our study, we did not speculate about the date of Proto-Indo-European and the locations of its speakers, as these questions are unresolved by our data, although we do think the genetic data impose constraints on what occurred. We are enthusiastic about the potential of genetics to contribute to a resolution of this longstanding issue, but this is likely to require DNA from multiple, as yet unsampled, ancient populations.

Klejn response to that:

Allegedly, I had accused the authors of tracing all Indo-European languages back to Yamnaya, whereas they did not trace all of them but only a portion! Well, I shall not reproach the authors for their ambiguous language: it remains the case that (beginning with the title of the first article) their qualifications are lost and their readers have understood them as presenting the solution to the whole question of the origins of Indo-European languages.

(…) they had in view not the Proto-Indo-European before the separation of the Hittites, but the language that was left after the separation. Yet, this was still the language ancestral to all the remaining Indo-European languages, and the followers of Sturtevan and Kluckhorst call only this language Proto-Indo-European (while they call the initial one Indo-Hittite). The majority of linguists (specialists in Indo-European languages) is now inclined to this view. True, the breakup of this younger language is several hundred years more recent (nearly a thousand years later according to some glottochronologies) than the separation of Anatolian languages, but it is still around a thousand years earlier than the birth of cultures derived from Yamnaya.
More than that, I analysed in my criticism both possibilities — the case for all Indo-European languages spreading from Yamnaya and the case for only some of them spreading from Yamnaya. In the latter case, it is argued that only the languages of the steppes, the Aryan (Indo- Iranian) are descended from Yamnaya, not the languages of northern Europe. Together with many scholars, I am in agreement with the last possibility. But, then, what sense can the proposed migration of the Yamnaya culture to the Baltic region have? It would bring the Indo-Iranian proto-language to that region! Yet, there are no traces of this language on the coasts of the Baltic!

My main concern is that, to my mind, one should not directly apply conclusions from genetics to events in the development of language because there is no direct and inevitable dependence between events in the life of languages, culture, and physical structure (both anthropological and genetic). They can coincide, but often they all follow divergent paths. In each case the supposed coincidence should be proved separately.

The authors’ third objection concerns the increase of the genetic similarity of European population with that of the Yamnaya culture. This increases in the north of Europe and is weak in the south, in the places adjacent to the Yamnaya area, i.e. in Hungary. This gradient is clearly expressed in the modern population, but was present already in the Bronze Age, and hence cannot be explained by shifts that occurred in the Early Iron Age and in medieval times. However, the supposed migration of the Yamnaya culture to the west and north should imply a gradient in just the opposite direction!

Regarding the arguments of Kristiansen and colleagues:

[They argue that] in two early burials of the Corded Ware culture (one in Germany, the other in Poland) some single attributes of Yamnaya origin have been found.

(…) if this is the full extent of Yamnaya infiltration into central Europe—two burials (one for each country) from several thousands (and from several hundreds of early burials)—then it hardly amounts to large-scale migration.

Quite recently we have witnessed the success of a group of geneticists from Stanford University and elsewhere (Poznik et al., 2016). They succeeded in revealing varieties of Y-chromosome connected with demographic expansions in the Bronze Age. Such expansion can give rise to migration. Among the variants connected with this expansion is R1b, and this haplogroup is typical for the Yamnaya culture. But what bad luck! This haplogroup connected with expansion is indicated by the clade L11, while the Yamnaya burials are associated with a different clade, Z2103, that is not marked by expansion. It is now time to think about how else the remarkable results reached by both teams of experienced and bright geneticists may be interpreted.

Regarding the work of Heyd,

(…) with regard to the barrow burials of the third millennium BC in the basin of the Danube, although they have been assigned to the Yamnaya culture, I would consider them as also belonging to
another, separate culture, perhaps a mixed culture: its burial custom is typical of the Yamnaya, but its pottery is absolutely not Yamnaya, but local Balkan with imports of distinctive corded beakers (Schnurbecher). I would not be surprised if
Y-chromosome haplogroups of this population were somewhat similar to those of the Yamnaya, while mitochondrial groups were indigenous. As yet, geneticists deal with great blocks of populations and prefer to match them to very large and generalized cultural blocks, while archaeology now analyses more concrete and smaller cultures, each of which had its own fate.

Iosif Lazaridis shares more thoughts on the discussion in his Twitter account:

As we mentioned in Haak, Lazaridis et al. (2015), the Yamnaya are the best proximate source for the new ancestry that first appears with the Corded Ware in central Europe, as it has the right mix of both ANE (related to Native Americans, MA1, and EHG), but also Armenian/Caucasus/Iran-like southern component of ancestry. The Yamnaya is a westward expansive culture that bears exactly the two new ancestral components (EHG + Caucasus/Iran/Armenian-like).
As for the Y-chromosome, it was already noted in Haak, Lazaridis et al. (2015) that the Yamnaya from Samara had Y-chromosomes which belonged to R-M269 but did not belong to the clade common in Western Europe (p. 46 of supplement). Also, not a single R1a in Yamnaya unlike Corded Ware (R1a-dominated). But Yamnaya samples = elite burials from eastern part of the Yamnaya range. Both R1a/R1b found in Eneolithic Samara and EHG, so in conclusion Yamnaya expansion still the best proximate source for the post-3,000 BCE population change in central Europe. And since 2015 steppe expansion detected elsewhere (Cassidy et al. 16, Martiniano et al. 17, Mittnik et al. 17, Mathieson et al. 17, Lazaridis et al. 2016 (South Asia) and …?…

I love the smell of new wording in the morning… viz. Yamnaya best proximate source for Corded Ware, Corded Ware might account for only a subset of Indo-European languages, Corded Ware representing Aryan languages (probably Klejn misinterprets what the authors mean, i.e. some kind of Indo-Slavonic or Germano-Balto-Slavic group)…

We shall expect more and more ambiguous rewording and more adjustments of previous conclusions as new papers and new criticisms appear.

Related:

Featured image from the article: Distribution of the ‘Yamnaya’ genetic component in the populations of Europe (data taken from Haak et al., 2015). The intensity of the colour corresponds to the contribution of this component in various modern populations