The future of the Reich Lab’s studies and interpretations of Late Indo-European migrations

yamna-corded-ware-bell-beaker-reich

Short report on advances in Genomics, and on the Reich Lab:

Some interesting details:

  • The Lab is impressive. I would never dream of having something like this at our university. I am really jealous of that working environment.
  • They are currently working on population transformations in Italy; I hope we can have at last Italic and Etruscan samples.
  • It is always worth it to repeat that we are all the source of multiple admixture events, many of them quite recent; and I liked the Star Wars simile.
  • Also, some names hinting at potential new samples?? Zajo-I, Chanchan, Gurulde?, Володарка (Ukraine – medieval?), Autodrom, Облевка, Кресты, Кудуксай (Ural region, palaeo-metal?), Золкут, etc.
reich-lab-samples
Ancient DNA sample bag?

On the bad aspect, they keep repeating the same “steppe ancestry” meme (in the featured image above, or the one below). I know this is the news report (i.e. science communication), not exactly the Reich Lab, but these maps didn’t appear out of the blue.

steppe-admixture-reich
Steppe ancestry distribution in Europe, according to PBS.

Interesting for future interpretations is the whiteboard behind David Reich’s back (apparently they like to keep relevant information on whiteboards…):

reich-indo-european-tree
Whiteboard behind David Reich’s back (at his office?).

It seems that while the Copenhagen group will still be bound (see here) by the Gimbutas/Kristiansen starting point, the Reich Lab will remain bound by Anthony’s selection of Ringe’s (2002) glottochronological model, and they will try to make genomic data fit in with it.

In fact, the whiteboard doesn’t even include Ringe’s link of Germanic with Italo-Celtic, which could maybe hint at Anthony’s recent change of heart? (i.e. Yamna Hungary -> Corded Ware). That would mean still less Linguistics (if glottochronology can be called that), and more Archaeology…

anthony-ringe-migration-model
Image from Anthony & Ringe (2015). “The Proto-Indo-European homeland, with migrations outward at about 4200 BCE (1), 3300 BCE (2), and 3000 BCE (3a and 3b). A tree diagram (inset) shows the pre-Germanic split as unresolved. Modified from Anthony (2013).”

I don’t know why university labs need to do this: To select the linguistic model preferred by a single archaeologist, which happens to be the lead archaeologist of the group, and then try to make genetic data agree again and again with that model. I guess it is a strategic question, and has to do with granting continued contacts with archaeological sites, and access to samples from them?

I understand none of them will try to learn ancient languages, too much work probably. But, wouldn’t it have been more scientifish, at least, to depart from, say, three or four reasonable potential linguistic models (that is, from Indo-Europeanists), and from there discuss the best potential fits for the current genomic data in each paper?

This is, for example, how the Heyd (archaeologist) + German/Spanish Indo-Europeanist schools would look like:

yamnaya-heyd-dunkel
Yamnaya expansion coupled with Meid’s (1975) description of three stages of Proto-Indo-European development (as interpreted by Adrados 1998) and depiction of Heyd’s proposal of Yamna expansion.

Wouldn’t you say it could have fitted the statistical and Y-DNA data seamlessly, in contrast to Gimbutas/Trager (i.e. Kristiansen today), or to Anthony/Ringe?

NOTE. I would say the mainstream German school follows Meid’s (1975) three-stage theory coupled with Dunkel’s (e.g. 1997) nomenclature. The Spanish school follows Adrados, who has repeated ad nauseam that he was the first to mention the three-stage theory in conferences and papers previous to and coincident with Meid’s proposal (see his latest JIES article, a paper available in Scribd). In any case, Spanish and German scholars have been working hand in hand in accepting and developing a general linguistic model similar to the one above.

Archaeological theories like those of Heyd or Mallory for Yamna and Bell Beaker (in contrast to Kristiansen or Anthony), and Prescott and Walderhaug for Bell Beaker and Germanic (contrasting with Kristiansen and Iversen) are compatible with this German/Spanish model.

The French school is non-existent on the homeland matter, Italian scholars seem to be behind even in the description of Anatolian as archaic (probably related to the general wish to have Latin as derived from Vergil’s Troy), Russian scholars are still working with Nostratic and Mesolithic expansions, and Leiden, as the leading IE publisher worldwide today, is full of very different ‘divos’, each with his own pet theory (some obviously agreeing with the German/Spanish model; and especially interesting is that some of them are strong supporters of an Indo-Uralic proto-language).

The English-speaking world, on the other hand, has seen the most varied models being either proposed or translated into its language, with the most popular ones being those publicized by archaeologists (Winfred P. Lehmann being one of the noteworthy exceptions), which may explain why for some people (archaeologists or geneticists) linguistics seems more like a game. It is to be assumed that these same people haven’t taken a look at the dozens of genetic papers published to date – and hundreds of archaeological papers using a bit of linguistics to support their models – , and how wrong they have all been in their interpretations, or else they would realize that genomics does (sadly) not really look like a serious discipline at all right now among most linguists, and among many archaeologists either…

Thus, instead of comparing the main theories on Proto-Indo-European (i.e. linguistics->archaeology->genetics), which would have offered the most stable framework to assess potential prehistoric ethnolinguistic identifications, they keep using a single, simplistic language tree liked by an archaeologist, and trying to fit genetic data to it, while also adapting archaeology to genetics, i.e. genetics->archaeology->linguistics; which, as you can imagine, is not going to convince any linguist.

Especially disappointing is that the world’s leading genetic lab still relies on a marginal proposal based on glottochronology, the homeopathy of linguistics… At least in that regard everyone should know better by now.

Also, they keep interacting with the wrong audience: instead of trying to engage linguists into the real homeland and dialectal quest, to keep Genomics a serious discipline among academics, they tend to discuss with politically- or racially-motivated people, which is probably also in line with strategic decisions.

In the example below, we see the main author of their recent paper on Indo-Iranian migrations seeking once again interaction, this time through “news” promoted by Hindu nationalist bigots, so that – even if that makes them look more neutral in the eyes of those who may allow access to Indian samples – , in the end, we see in genomics a fictitious revival of the “AIT vs. OIT debate” dead long ago in linguistics and archaeology (anywhere but in India).

Pretty disappointing to see these trends; so much effort and time invested in futile discussions and infinitely reworked doomed glottochronological or 19th-century models, when it is the fine-scale population structure of expanding Yamna peoples what we should be discussing now, and thus Late PIE dialectalisation with offshoots Afanasevo, East Bell Beaker, Balkan Bronze Age, and Sintashta/Potapovka; as well as Corded Ware evolution in Uralic-speaking territory.

EDIT (7 JUN 2018): Some parts of the text have been corrected or slightly modified.

Related:

FADS1 and the timing of human adaptation to agriculture

fads1-farmers

Open access FADS1 and the timing of human adaptation to agriculture, by Sara Mathieson & Iain Mathieson, bioRxiv (2018).

Abstract:

Variation at the FADS1/FADS2 gene cluster is functionally associated with differences in lipid metabolism and is often hypothesized to reflect adaptation to an agricultural diet. Here, we test the evidence for this relationship using both modern and ancient DNA data. We document pre-out-of-Africa selection for both the derived and ancestral FADS1 alleles and show that almost all the inhabitants of Europe carried the ancestral allele until the derived allele was introduced approximately 8,500 years ago by Early Neolithic farming populations. However, we also show that it was not under strong selection in these populations. Further, we find that this allele, and other proposed agricultural adaptations including variants at LCT/MCM6, SLC22A4 and NAT2, were not strongly selected until the Bronze Age, 2,000-4,000 years ago. Similarly, increased copy number variation at the salivary amylase gene AMY1 is not linked to the development of agriculture although in this case, the putative adaptation precedes the agricultural transition. Our analysis shows that selection at the FADS locus was not tightly linked to the development of agriculture. Further, it suggests that the strongest signals of recent human adaptation may not have been driven by the agricultural transition but by more recent changes in environment or by increased efficiency of selection due to increases in effective population size.

Interesting excerpt for the steppe-related expansion:

agricultural-adaptation-allele-frequency
Allele frequency trajectories for other putative agricultural adaptation variants. As in Figure 2C, estimated allele frequency trajectories and selection coefficients in different ancient European populations. Significant selection coefficients are labelled.

In the case of FADS1 and all the other examples we investigated, the proposed agricultural adaption was either not temporally linked with agriculture or showed no evidence of selection in agricultural populations. Instead, most of the variants with any evidence of selection were only strongly selected at some point between the Bronze Age and the present day, that is, in a period starting 2000-4000 BP and continuing until the present. This time period is one in which there is relatively limited ancient DNA data, and so we are unable to determine the timing of selection any more accurately. Future research should address the question of why this recent time period saw the most rapid changes in apparently diet associated genes. One plausible hypothesis is that the change in environment at this time was actually more dramatic than the earlier change associated with agriculture. Another is that effective population sizes were so small before this time that selection did not operate efficiently on variants with small selection coefficients. For example, analysis of present-day genomes from the United Kingdom suggests that effective population size increased by a factor of 100-1000 in the past 4500 years (Browning and Browning 2015). Ancient effective population sizes less that 104 would suggest that those populations would not be able to efficiently select for variants with selection coefficients on the order of 10-4 or smaller. Larger ancient DNA datasets from the past 4,000 years will likely resolve this question.

This complexity of the reasons for selection reminded me of the comment by Narasimhan on lactase persistence expanding with steppe populations into Central Asia (based on data of the paper where he is the first author):

I always thought that to argue for natural selection in humans (viz. skin color, lactase persistence, etc.) was possible for archaic groups over tens of thousands of years, but that more recent selections would be very difficult to prove, in so far as historical population expansions involve more ‘artificial’ (i.e. man-made or man-caused) societal changes.

NOTE. I am probably more inclined to think about regional outbreaks (especially of new diseases) as one of the few potential short-term selection mechanisms in historical societies, because of their potential to create sudden bottlenecks of better fitted survivors.

I think recent works like these are showing a mixed situation, where maybe some traits were strongly selected for environmental reasons; but most of the time they were probably – like, say, Y-DNA haplogroup bottlenecks in Europe after the steppe-related expansions – due mostly to chance.

The new Scicomm’s warhorse is “CHG ancestry = PIE” and the Iranian homeland

invasion-from-the-steppe-yamnaya

Funny reports are popping up due to a recent article in New Scientist (behind paywall), World’s most-spoken languages may have arisen in ancient Iran, which echoes the controversial interpretations of Wang et al. (2018).

I have been waiting to read the printed edition, but that of May 26th doesn’t have the article in it, so it may be a web-only text.

Nevertheless, here are some excerpts about the PIE homeland from a news aggregator that caught my attention (emphasis mine):

The two proposed locations are divided by the Caucasus mountains, which are found between the Black and Caspian Seas. In today’s geography, the mountains cover parts of Russia, Georgia, Azerbaijan, and Armenia.

To find out whether the ancient language came from north or south of these mountains, a team from the Max Planck Institute for the Science of Human History looked at the bones of 45 ancient humans from the Caucasus region, and analyzed their DNA. These people lived in the area between 3,200 and 6,500 years ago.

Interestingly, from looking at their genes, the researchers determined that these ancient people seemed to be moving predominantly in one direction – they were heading north. This suggests that, contrary to what was previously believed, the first Indo-European language might actually have arisen south of the Caucasus mountains, only spreading to other parts of Europe and Asia as people migrated north from this region. The findings are currently available on BioRxiv.

We know that the Proto-Indo-European language appeared somewhere between 5,500 and 9,000 years ago, and the study suggests it only spread to Europe about 6,500 years ago. Therefore, this lost language could have originated south of the Caucasus.

What’s more, the ancient people analyzed had similar genetic signatures to prehistoric farmers who once lived in western Iran. Therefore, the ancient version of many of our languages may have first evolved in ancient Iran, before spreading with the people who first spoke it, and their ancestors, as they radiated north of the Caucasus mountains to the Eurasian steppe.

However, there are still many who favor the conflicting theory – that the Proto-Indo-European language arose in the Eurasian steppe. But this would only take the language back about 4,800 years – when people moved from the Eurasian steppe into Europe – and specialists think the language is significantly older. The idea that it first sprung up in Iran about 6,500 years ago follows this assumption.

It seems that – now that the Danish workgroup (responsible for the “steppe ancestry = Indo-European” and “Corded Ware expanded from Yamna“) is backing down, and both it and the Reich/Jena group are accepting that Yamna represents the expansion of Late Indo-European into Afanasevo, Bell Beaker, and Sintashta – anything before Yamna in the steppe is just another “conflicting theory” among equals…

So forget the “steppe ancestry = PIE”, and welcome the newly fashionable “CHG ancestry = PIE“, and of course the Iranian homeland.

This is how I imagine genetic labs writing anthropological interpretations and conclusions of their papers, against every single reasonable restraint (and the well-established models of linguists and archaeologists) and then publicizing them:

mr-bean-middle-finger

Related:

David Reich on social inequality and Yamna expansion with few Y-DNA subclades

Interesting article from David Reich that I had missed, at Nautilus, Social Inequality Leaves a Genetic Mark.

It explores one of the main issues we are observing with ancient DNA, the greater reduction in Y-DNA lineages relative to mtDNA lineages, and its most likely explanation (which I discussed recently).

Excerpts interesting for the Indo-European question (emphasis mine):

Gimbutas’s reconstruction has been criticized as fantastical by her critics, and any attempt to paint a vivid picture of what a human culture was like before the period of written texts needs to be viewed with caution. Nevertheless, ancient DNA data has provided evidence that the Yamnaya were indeed a society in which power was concentrated among a small number of elite males. The Y chromosomes that the Yamnaya carried were nearly all of a few types, which shows that a limited number of males must have been extraordinarily successful in spreading their genes. In contrast, in their mitochondrial DNA, the Yamnaya had more diverse sequences.9 The descendants of the Yamnaya or their close relatives spread their Y chromosomes into Europe and India, and the demographic impact of this expansion was profound, as the Y-chromosome types they carried were absent in Europe and India before the Bronze Age but are predominant in both places today.13

This Yamnaya expansion also cannot have been entirely friendly, as is clear from the fact that the proportion of Y chromosomes of steppe origin in both western Europe14 and in India15 today is much larger than the proportion of the rest of the genome. This preponderance of male ancestry coming from the steppe implies that male descendants of the Yamnaya with political or social power were more successful at competing for local mates than men from the local groups. The most striking example I know is from Iberia in far southwestern Europe, where Yamnaya-derived ancestry arrived suddenly at the onset of the Bronze Age between 4,500 and 4,000 years ago. Daniel Bradley’s laboratory and my laboratory independently produced ancient DNA from individuals of this period.14 We find that in the first Iberians with Yamnaya-derived ancestry, the proportion of Yamnaya ancestry across the whole genome is almost never more than around 15 percent. However, around 90 percent of males who carry Yamnaya ancestry have a Y-chromosome type of steppe origin that was absent in Iberia prior to that time. It is clear that there were extraordinary hierarchies and imbalances in power at work in the Yamnaya expansions.

David Reich clearly doesn’t give a damn about how other people might react to his commentaries. That’s nice.

In any case, if anyone was still in denial, R1b-M269 expanded with Yamna (through the Bell Beaker expansion) into Iberia, hence yes, 90% of modern Basque male lineages have an origin in the steppe, like the R1b-DF27 sample recently found, and their common ancestor spoke Late Proto-Indo-European.

Findings like these, which should be taken as normal developments of research, are apparently still a trauma for many – like R1a-fans from India realizing most of their paternal ancestors came from the steppe, or its fans from Northern Europe understanding that their paternal ancestors probably spoke Uralic or a related language; or N1c-fans seeing how their paternal ancestors probably didn’t speak Uralic. It seems life isn’t fair to stupid simplistic ethnolinguistic ideas

Let’s see which Y-DNA haplogroups we find in West Yamna, to verify the latest migration model of Late PIE speakers of the Reich Lab (featured image).

Check out also the BBC News coverage of David Reich and Nick Patterson, the two most influential researchers of the moment in Human Ancestry: How ancient DNA is transforming our view of the past.

Related:

The uneasy relationship between Archaeology and Ancient Genomics

Allentoft Corded Ware

News feature Divided by DNA: The uneasy relationship between archaeology and ancient genomics, Two fields in the midst of a technological revolution are struggling to reconcile their views of the past, by Ewen Callaway, Nature (2018) 555:573-576.

Interesting excerpts (emphasis mine):

In duelling 2015 Nature papers6,7the teams arrived at broadly similar conclusions: an influx of herders from the grassland steppes of present-day Russia and Ukraine — linked to Yamnaya cultural artefacts and practices such as pit burial mounds — had replaced much of the gene pool of central and Western Europe around 4,500–5,000 years ago. This was coincident with the disappearance of Neolithic pottery, burial styles and other cultural expressions and the emergence of Corded Ware cultural artefacts, which are distributed throughout northern and central Europe. “These results were a shock to the archaeological community,” Kristiansen says.

(…)

Still, not everyone was satisfied. In an essay8 titled ‘Kossinna’s Smile’, archaeologist Volker Heyd at the University of Bristol, UK, disagreed, not with the conclusion that people moved west from the steppe, but with how their genetic signatures were conflated with complex cultural expressions. Corded Ware and Yamnaya burials are more different than they are similar, and there is evidence of cultural exchange, at least, between the Russian steppe and regions west that predate Yamnaya culture, he says. None of these facts negates the conclusions of the genetics papers, but they underscore the insufficiency of the articles in addressing the questions that archaeologists are interested in, he argued. “While I have no doubt they are basically right, it is the complexity of the past that is not reflected,” Heyd wrote, before issuing a call to arms. “Instead of letting geneticists determine the agenda and set the message, we should teach them about complexity in past human actions.”

Many archaeologists are also trying to understand and engage with the inconvenient findings from genetics. (…)
[Carlin:] “I would characterize a lot of these papers as ‘map and describe’. They’re looking at the movement of genetic signatures, but in terms of how or why that’s happening, those things aren’t being explored,” says Carlin, who is no longer disturbed by the disconnect. “I am increasingly reconciling myself to the view that archaeology and ancient DNA are telling different stories.” The changes in cultural and social practices that he studies might coincide with the population shifts that Reich and his team are uncovering, but they don’t necessarily have to. And such biological insights will never fully explain the human experiences captured in the archaeological record.

Reich agrees that his field is in a “map-making phase”, and that genetics is only sketching out the rough contours of the past. Sweeping conclusions, such as those put forth in the 2015 steppe migration papers, will give way to regionally focused studies with more subtlety.

This is already starting to happen. Although the Bell Beaker study found a profound shift in the genetic make-up of Britain, it rejected the notion that the cultural phenomenon was associated with a single population. In Iberia, individuals buried with Bell Beaker goods were closely related to earlier local populations and shared little ancestry with Beaker-associated individuals from northern Europe (who were related to steppe groups such as the Yamnaya). The pots did the moving, not the people.

This final paragraph apparently sums up a view that Reich has of this field, since he repeats it:

Reich concedes that his field hasn’t always handled the past with the nuance or accuracy that archaeologists and historians would like. But he hopes they will eventually be swayed by the insights his field can bring. “We’re barbarians coming late to the study of the human past,” Reich says. “But it’s dangerous to ignore barbarians.”

I would say that the true barbarians didn’t have a habit or possibility to learn from the higher civilizations they attacked or invaded. Geneticists, on the other hand, only have to do what they expect archaeologists to do: study.

EDIT (30 MAR 2018): A new interesting editorial of Nature, On the use and abuse of ancient DNA.

See also:

Population substructure in Iberia, highest in the north-west territory (to appear in Nature)

A manuscript co-authored by Angel Carracedo, from the University of Santiago de Compostela, and (always according to him) pre-accepted in Nature, will offer more insight into the population substructure of Spain, based on autosomal DNA.

Carracedo’s lecture about DNA (in Galician), including his summary of the paper (from december 2017):

Some of the points made in the video:

  • The study shows a situation parallelling – as expected – the expansion of Spanish Medieval kingdoms during the Reconquista (and subsequent repopulation).
  • In it, the biggest surprise seems to be the greater substructure found in Galicia, the north-western Spanish territory – greater even than expected by the authors.
  • As a side note, Galicia shows a great influence from Moorish” ancestral components, due mainly to the influx from Portugal, which shows more.

It is difficult to judge only from the image and his words, but one could say that there are:

  • Certain quite old ancestral Galician groups;
    • then two – also quite old – ancestral Basque groups;
      • then more recent Galician groups;
        • and then a common, central Spanish group – including
          • a wider Asturian-Catalan group, with a western Asturian-Leonese, and an eastern Catalan subgroup;
          • and a central Castillian-Aragonese group, also with a western Castillian, and an eastern Aragonese subgroup.
spain-autosomal
Spain’s population substructure, from the video.

We thought that certain parts of the British Isles could show ancestral components related to the old population, although this has not proven exactly right, due to more recent population expansions.

However, this paper might shed light to the controversy surrounding Lusitanian (possibly Gallaico-Lusitanian) as a Pre-Celtic Indo-European group of Iberia, either slightly older as an Italo-Celtic dialect, or potentially from the Bell Beaker expansion, whose genetic imprint might have survived the Roman conquest, which apparently didn’t replace its ancestral population.

Given the presence of a central Spanish group opposed to the other minor groups – and knowing that (at least part of) the Medieval kingdoms should be related to the Occitan region – due to the Celtic expansion, and also potentially later during the Visigothic Kingdom, and the Carolingian Empire – , we can only guess that the other (north-western and Basque) groups are potentially quite old, and reflect prehistoric population structures.

Just speculating here, of course. Another interesting genetic paper to await…

Seen first in the Facebook group Iberia ADN.

Related:

Integrative studies of cultural evolution: crossing disciplinary boundaries to produce new insights

Interesting open access article Integrative studies of cultural evolution: crossing disciplinary boundaries to produce new insights, Oren Kolodny, Marcus W. Feldman, Nicole Creanza, Philos. Trans. Royal Soc. B (2018).

Abstract:

Culture evolves according to dynamics on multiple temporal scales, from individuals’ minute-by-minute behaviour to millennia of cultural accumulation that give rise to population-level differences. These dynamics act on a range of entities—including behavioural sequences, ideas and artefacts as well as individuals, populations and whole species—and involve mechanisms at multiple levels, from neurons in brains to inter-population interactions. Studying such complex phenomena requires an integration of perspectives from a diverse array of fields, as well as bridging gaps between traditionally disparate areas of study. In this article, which also serves as an introduction to the current special issue, we highlight some specific respects in which the study of cultural evolution has benefited and should continue to benefit from an integrative approach. We showcase a number of pioneering studies of cultural evolution that bring together numerous disciplines. These studies illustrate the value of perspectives from different fields for understanding cultural evolution, such as cognitive science and neuroanatomy, behavioural ecology, population dynamics, and evolutionary genetics. They also underscore the importance of understanding cultural processes when interpreting research about human genetics, neuroscience, behaviour and evolution.

Related:

Science and Archaeology (Humanities): collaboration or confrontation?

Allentoft Corded Ware

Another discussion on the role of Science for Archaeology, in The Two Cultures and a World Apart: Archaeology and Science at a New Crossroads, by Tim Flohr Sørensen, Norwegian Archaeological Review, vol. 50, 2 (2017):

Within the past decade or so, archaeology has increasingly utilised and contributed to major advances in scientific methods when exploring the past. This progress is frequently celebrated as a quantum leap in the possibilities for understanding the archaeological record, opening up hitherto inaccessible dimensions of the past. This article represents a critique of the current consumption of science in archaeology, arguing that the discipline’s grounding in the humanities is at stake, and that the notion of ‘interdisciplinarity’ is becoming distorted with the increasing fetishisation of ‘data’, ‘facts’ and quantitative methods. It is argued that if archaeology is to break free of its self-induced inferiority to and dependence on science, it must revitalise its methodology for asking questions pertinent to the humanities.

Commentators in the discussion include:

The answer of Sørensen to them is on Archaeological Paradigms: Pendulum or Wrecking Ball?. Excerpts:

Thus, I argue that what we are witnessing with ‘the third science revolution’ (Kristiansen 2014) is precisely the proliferation of an already very authoritative science ideal in archaeology. And I worry that this dominance will limit research possibilities and potentials rather than encouraging plurality and radical experimentation with different forms of knowing.
(…)
I do believe in the coexistence of disparate academic principles and that collaboration is very often necessary, but I am also of the conviction that some degree of epistemological friction keeps both fields of research progressing. Nurturing distinctions, in other words, is no less useful than aiming for assimilation. What I am arguing for is thus a more respectful friction than the one characterising the processual/post-processual collisions, hoping for an academic environment where differences between research ideals are humbly accepted and cultivated precisely for their disparate strengths.
(…)
So, what I am arguing for is a more kaleidoscopic academic landscape, where different positions do not always have to assume a defensive or compromising stance, especially in confrontation with paradigms that are prospering politically. This also implies that science is not simply in the service of archaeology, as Lidén argues, but that we need to consider how archaeology may benefit science more generally by continuing to debate epistemological grounds, methodology and our modes of inquiry. And so, my fellow archaeologists: ask not what science can do for us, but what we can do for science.
(…)
In my original article, I addressed the widespread tendency in archaeology to disseminate research findings with sometimes too much conviction, where ambiguous results (and limited statistical data) are adopted with little concern for the inherent uncertainties. It is precisely this valorisation and authority of scientific observations that I claim to lead to an implicit devaluation of studies based in the humanities. The problem is – as stated numerous times in my original article – not science, but the consumption of scientific observations in archaeology, where the subtleties and not least ambiguities of scientific results are filtered out, leaving space almost exclusively for scientifically ‘proven’ facts and unequivocal results. This mode of consumption stands in direct contrast to the epistemological observation in the sciences, dictating that ‘“proof” and “certainty” are actually in short supply in the world of science’ (Freudenburg et al. 2008, p. 5). Hence, the risk is that archaeology somewhat uncritically adopts scientific observations that are in fact ‘empirically underdetermined – based largely on evidence that is in the category of the “maybe,” being inherently ambiguous rather than being absolutely clear-cut’ (Freudenburg et al. 2008, p. 6).

As I said recently on the article Massive Migrations…, by Martin Furholt, we are living a historical debate on essential questions for the future of all these disciplines.

And, as always, there is no shortcut to reading the texts. Unlike in Science, you cannot write a table with a summary of findings…

Discovered (again) via a comment on this blog by Joshua Jonathan.

Featured image from Allentoft et al. “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.”

Related:

Differences in ADMIXTURE between Khvalynsk/Yamna and Sredni Stog/Corded Ware

neolithic-steppe

Looking for differences among steppe cultures in Genomics is like looking for a needle in a haystack.

It means, after all, looking for differences among closely related cultures, such as between South-Western and North-Western Anatolian Neolithic cultures, or among Old European cultures (such as Vinča or Cucuteni–Trypillia), or between Iberian cultures after the arrival of steppe-related populations.

These differences between closely related regions, in all these cases and especially among steppe cultures, even when they are supported by Archaeology and anthropological models of migration (and compatible with linguistic models), are expected to be minimal.

Fortunately, we have phylogeography, which helps us point in the right direction when assessing potential migrations using genomic data.

User Tomenable recently pointed out a curious finding on Anthrogenica, from data available in Mathieson et al (2017): in ADMIXTURE results with K=12, a different ancestral component (in light green in the paper, see below) is traceable from the North Caspian steppe since the Neolithic. This is also partially distinguishable on K=10 and K=11, although not so clearly differentiating among later cultures.

NOTE: Read more on the controversy regarding the ideal number of ancestral populations, the absurd use of ADMIXTURE to solve language questions, and the meaning of cross-validation (CV) values

admixture-khvalynsk-yamna-sredni-stog-cwc
Unsupervised ADMIXTURE plot from k=10 to 12, on a dataset consisting of 1099 present-day individuals and 476 ancient individuals. We show newly reported ancient individuals and some previously published individuals for comparison.

Explanations for this finding might include, as the user points out, a greater contribution of CHG ancestry in the eastern steppe cultures (Khvalynsk/Yamna) compared to the North Pontic steppe (Sredni Stog/Corded Ware), which is probably one of the main genomic differences among both cultures, as I pointed out in the Indo-European demic diffusion model (see accounts on the origins of Khvalynsk and Sredni Stog populations and on contacts between Yamna and the Caucasus, and see below also my sketch of Eurasian genomic history).

Interesting is also the appearance of similar ancestral components later in Vučedol – which probably received admixture from Yamna settlers (see admixture components in West Yamna samples and in the Yamna settler from Bulgaria) – , and later still in the Balkans.

On the other hand, previous ancestral components in outliers from the Balkans seem to be more similar to Sredni Stog samples, giving still more strength to the hypothesis that this common (“steppe”) component expanded westward within the Pontic-Caspian steppe with the spread of Suvorovo-Novodanilovka chiefs.

Problems with this interpretation include:

1) The scarce samples available, the different cultures included, and the CV values of the K populations selected in ADMIXTURE.

2) The lack of data for comparison with Bell Beaker peoples (from Olalde et al. 2017).

3) The sample classified as Latvia_LN/CWC has this component. I have already said before that, given the differences with all other Corded Ware samples, this quite early sample might be an outlier, with Khvalynsk/Yamna population connected directly to the ancestors of this individual, possibly through exogamy (as it is clear from my sketch below). Whether or not this is an outlier among CWC populations in the Baltic, only future samples can tell.

4) Three later individuals from Corded Ware in Germany have the component, in a minimal amount. I would bet – judging by their position in the graphic – that this might be explained through the Esperstedt family. These individuals might have in turn got the contribution directly from the oldest member, who shows what seems (in PCA) like a recent admixture from contemporary steppe cultures (such as the Catacomb culture).

NOTE: See my graphics with interesting members of the Espersted family marked: ADMIXTURE and PCA (outlier).

qgraph-eurasia
Tentative sketch modelling the genetic history of Europe and West Eurasia from ancient populations up to the Neolithic, according to results in recent genetic papers and archaeological models of known migrations.

Again, needle in a haystack… And confirmation bias by me, indeed.

But interesting nonetheless.

EDIT (4 JAN 2017): A reader points out that the interpretation of Unsupervised ADMIXTURE should work backwards (i.e. different contributions into different modern populations), and not based solely on ancestral populations, which seems probably right. So again, confirmation bias (and potentially wrong direction fallacy) by me…

Related:

Genomic history of Northern Eurasians includes East-West and North-South gradients

russia-uralic-ibd

Open Access article on modern populations (including ancient samples), Between Lake Baikal and the Baltic Sea: genomic history of the gateway to Europe, by Triska et al., BMC Genetics 18(Suppl 1):110, 2017.

Abstract:

Background
The history of human populations occupying the plains and mountain ridges separating Europe from Asia has been eventful, as these natural obstacles were crossed westward by multiple waves of Turkic and Uralic-speaking migrants as well as eastward by Europeans. Unfortunately, the material records of history of this region are not dense enough to reconstruct details of population history. These considerations stimulate growing interest to obtain a genetic picture of the demographic history of migrations and admixture in Northern Eurasia.

Results
We genotyped and analyzed 1076 individuals from 30 populations with geographical coverage spanning from Baltic Sea to Baikal Lake. Our dense sampling allowed us to describe in detail the population structure, provide insight into genomic history of numerous European and Asian populations, and significantly increase quantity of genetic data available for modern populations in region of North Eurasia. Our study doubles the amount of genome-wide profiles available for this region.

We detected unusually high amount of shared identical-by-descent (IBD) genomic segments between several Siberian populations, such as Khanty and Ket, providing evidence of genetic relatedness across vast geographic distances and between speakers of different language families. Additionally, we observed excessive IBD sharing between Khanty and Bashkir, a group of Turkic speakers from Southern Urals region. While adding some weight to the “Finno-Ugric” origin of Bashkir, our studies highlighted that the Bashkir genepool lacks the main “core”, being a multi-layered amalgamation of Turkic, Ugric, Finnish and Indo-European contributions, which points at intricacy of genetic interface between Turkic and Uralic populations. Comparison of the genetic structure of Siberian ethnicities and the geography of the region they inhabit point at existence of the “Great Siberian Vortex” directing genetic exchanges in populations across the Siberian part of Asia.

EEHG-CHG-Neolithic_Farmer-ANE
f3 values to estimate (a) Eastern European Hunter-Gatherer, b Neolithic Farmer, c Caucasus hunter-gatherer, and d) Mal’ta (Ancient North Eurasian) ancestry in modern humans

Slavic speakers of Eastern Europe are, in general, very similar in their genetic composition. Ukrainians, Belarusians and Russians have almost identical proportions of Caucasus and Northern European components and have virtually no Asian influence. We capitalized on wide geographic span of our sampling to address intriguing question about the place of origin of Russian Starovers, an enigmatic Eastern Orthodox Old Believers religious group relocated to Siberia in seventeenth century. A comparative reAdmix analysis, complemented by IBD sharing, placed their roots in the region of the Northern European Plain, occupied by North Russians and Finno-Ugric Komi and Karelian people. Russians from Novosibirsk and Russian Starover exhibit ancestral proportions close to that of European Eastern Slavs, however, they also include between five to 10 % of Central Siberian ancestry, not present at this level in their European counterparts.

russian-uralic-turkicadmixture
Admixture proportions in studied populations, K = 6. Populations from the Extended dataset. Abbreviated population codes: NSK – Russians from Novosibirsk; STV -Starover Russians; ARK: Bashkirs from Arkhangelskiy district; BRZ – Bashkirs from Burzyansky district

Conclusions
Our project has patched the hole in the genetic map of Eurasia: we demonstrated complexity of genetic structure of Northern Eurasians, existence of East-West and North-South genetic gradients, and assessed different inputs of ancient populations into modern populations.

Featured image, from the article: “Departures from the expected IBD. Shown populations exceed the expected IBD sharing by more than two standard deviations.”

Related: