I basically added information from the latest papers published, which (luckily enough for me) haven’t been too many, and I have added images to illustrate certain sections.
I have updated the PCAs by including North Caucasus samples from Wang et al. (2018), whose position I could only infer for older versions from previously published PCA graphs.
I have also added to the supplementary materials the “Tip of the Iceberg” R1b tree by Mike Walsh from the FTDNA R1b group, with permission, because some relevant genetic sections are centered on the evolution of R1b lineages, and the reader can get easily lost with so many subclades.
I have also updated maps, including some of the Y-DNA ones, and managed to finish two new maps I was working on, and I added them to the supplementary materials and to the menu above:
It is tentative because there hasn’t been any professional study or amateur attempt to date to differentiate both “steppe ancestries” in Yamna, and especially in Bell Beakers. So much for the call of professional geneticists since 2018 (see here and here) and archaeologists since 2017 (see e.g. here and here) to distinguish fine-scale population structure to be able to follow neighbouring populations which expanded with different archaeological (and thus ethnolinguistic) groups.
I think both maps are especially important today, given the current Nordicist reactionary trends arguing (yet again) for an origin of Indo-Europeans in The North™, now based on the Fearsome Tisza River hypothesis, on cephalic index values, and a few pairwise comparisons – i.e. an absolutely no-nonsense approach to the Indo-European question (LOL). At least I get to relax and sit this year out just observing how other people bury themselves and their beloved “steppe ancestry=IE” under so many new pet theories…
NOTE. Not that there is anything wrong with a northern origin of North-West Indo-European from a linguistic point of view, as I commented recently – after all, a Corded Ware origin would roughly fit the linguistic guesstimates, unlike the proposed ancestral origins in Anatolia or India. The problem is that, like many other fringe theories, it is today just based on tradition, or (even worse) ethnic, political, or personal desires, and it doesn’t make sense when all findings from disciplines involved in the Indo-European and Uralic questions are combined.
Within 20 or 30 years, when genetic genealogists (or amateur geneticists, or however you want to call them) ask why we had the opportunity since 2015 to sample as many Hungarian Yamnaya individuals as possible and we didn’t, when it is clear that the number of unscathed kurgans is diminishing every year (from an estimated 4,000 in the 20th century, of the original tens of thousands, to less than 1,500 today) the answer will not be “because this or that archaeologist or linguist was a dilettante or a charlatan‘, as they usually describe academics they dislike.
It will be precisely because the very same genetic genealogists – supposedly interested today in the origin of R1b-L151 and/or genetic marker associated with North-West Indo-Europeans – are obsessed with finding them anywhere else but for Hungary, and prefer to use their money and time to play with a few statistical tools within a biased framework of flawed assumptions and study designs, obtaining absurd results and accepting far-fetched interpretations of them, to be told exactly what they want to hear: be it the Franco-Cantabrian homeland, the Dutch or Moravian Beaker from CWC homeland, the Maykop homeland, or the Moon homeland.
Poetic justice this heritage destruction, whose indirect causes will remain written in Internet archives for everyone to see, as a good lesson for future generations.
Experienced researchers, particularly those interested in population structure and historical inference, typically present STRUCTURE results alongside other methods that make different modelling assumptions. These include TreeMix, ADMIXTUREGRAPH, fineSTRUCTURE, GLOBETROTTER, f3 and D statistics, amongst many others. These models can be used both to probe whether assumptions of the model are likely to hold and to validate specific features of the results. Each also comes with its own pitfalls and difficulties of interpretation. It is not obvious that any single approach represents a direct replacement as a data summary tool. Here we build more directly on the results of STRUCTURE/ADMIXTURE by developing a new approach, badMIXTURE, to examine which features of the data are poorly fit by the model. Rather than intending to replace more specific or sophisticated analyses, we hope to encourage their use by making the limitations of the initial analysis clearer.
The default interpretation protocol
Most researchers are cautious but literal in their interpretation of STRUCTURE and ADMIXTURE results, as caricatured in Fig. 1, as it is difficult to interpret the results at all without making several of these assumptions. Here we use simulated and real data to illustrate how following this protocol can lead to inference of false histories, and how badMIXTURE can be used to examine model fit and avoid common pitfalls.
STRUCTURE and ADMIXTURE are popular because they give the user a broad-brush view of variation in genetic data, while allowing the possibility of zooming down on details about specific individuals or labelled groups. Unfortunately it is rarely the case that sampled data follows a simple history comprising a differentiation phase followed by a mixture phase, as assumed in an ADMIXTURE model and highlighted by case study 1. Naïve inferences based on this model (the Protocol of Fig. 1) can be misleading if sampling strategy or the inferred value of the number of populations K is inappropriate, or if recent bottlenecks or unobserved ancient structure appear in the data. It is therefore useful when interpreting the results obtained from real data to think of STRUCTURE and ADMIXTURE as algorithms that parsimoniously explain variation between individuals rather than as parametric models of divergence and admixture.
For example, if admixture events or genetic drift affect all members of the sample equally, then there is no variation between individuals for the model to explain. Non-African humans have a few percent Neanderthal ancestry, but this is invisible to STRUCTURE or ADMIXTURE since it does not result in differences in ancestry profiles between individuals. The same reasoning helps to explain why for most data sets—even in species such as humans where mixing is commonplace—each of the K populations is inferred by STRUCTURE/ADMIXTURE to have non-admixed representatives in the sample. If every individual in a group is in fact admixed, then (with some exceptions) the model simply shifts the allele frequencies of the inferred ancestral population to reflect the fraction of admixture that is shared by all individuals.
Several methods have been developed to estimate K, but for real data, the assumption that there is a true value is always incorrect; the question rather being whether the model is a good enough approximation to be practically useful. First, there may be close relatives in the sample which violates model assumptions. Second, there might be “isolation by distance”, meaning that there are no discrete populations at all. Third, population structure may be hierarchical, with subtle subdivisions nested within diverged groups. This kind of structure can be hard for the algorithms to detect and can lead to underestimation of K. Fourth, population structure may be fluid between historical epochs, with multiple events and structures leaving signals in the data. Many users examine the results of multiple K simultaneously but this makes interpretation more complex, especially because it makes it easier for users to find support for preconceptions about the data somewhere in the results.
In practice, the best that can be expected is that the algorithms choose the smallest number of ancestral populations that can explain the most salient variation in the data. Unless the demographic history of the sample is particularly simple, the value of K inferred according to any statistically sensible criterion is likely to be smaller than the number of distinct drift events that have practically impacted the sample. The algorithm uses variation in admixture proportions between individuals to approximately mimic the effect of more than K distinct drift events without estimating ancestral populations corresponding to each one. In other words, an admixture model is almost always “wrong” (Assumption 2 of the Core protocol, Fig. 1) and should not be interpreted without examining whether this lack of fit matters for a given question.
Because STRUCTURE/ADMIXTURE accounts for the most salient variation, results are greatly affected by sample size in common with other methods. Specifically, groups that contain fewer samples or have undergone little population-specific drift of their own are likely to be fit as mixes of multiple drifted groups, rather than assigned to their own ancestral population. Indeed, if an ancient sample is put into a data set of modern individuals, the ancient sample is typically represented as an admixture of the modern populations (e.g., ref. 28,29), which can happen even if the individual sample is older than the split date of the modern populations and thus cannot be admixed.
This paper was already available as a preprint in bioRxiv (first published in 2016) and it is incredible that it needed to wait all this time to be published. I found it weird how reviewers focused on the “tone” of the paper. I think it is great to see files from the peer review process published, but we need to know who these reviewers were, to understand their whiny remarks… A lot of geneticists out there need to develop a thick skin, or else we are going to see more and more delays based on a perceived incorrect tone towards the field, which seems a rather subjective reason to force researchers to correct a paper.
A potential hindrance to our advice to upgrade from PCA graphs to PCA biplots is that the SNPs are often so numerous that they would obscure the Items if both were graphed together. One way to reduce clutter, which is used in several figures in this article, is to present a biplot in two side-by-side panels, one for Items and one for SNPs. Another stratagem is to focus on a manageable subset of SNPs of particular interest and show only them in a biplot in order to avoid obscuring the Items. A later section on causal exploration by current methods mentions several procedures for identifying particularly relevant SNPs.
One of several data transformations is ordinarily applied to SNP data prior to PCA computations, such as centering by SNPs. These transformations make a huge difference in the appearance of PCA graphs or biplots. A SNPs-by-Items data matrix constitutes a two-way factorial design, so analysis of variance (ANOVA) recognizes three sources of variation: SNP main effects, Item main effects, and SNP-by-Item (S×I) interaction effects. Double-Centered PCA (DC-PCA) removes both main effects in order to focus on the remaining S×I interaction effects. The resulting PCs are called interaction principal components (IPCs), and are denoted by IPC1, IPC2, and so on. By way of preview, a later section on PCA variants argues that DC-PCA is best for SNP data. Surprisingly, our literature survey did not encounter even a single analysis identified as DC-PCA.
The axes in PCA graphs or biplots are often scaled to obtain a convenient shape, but actually the axes should have the same scale for many reasons emphasized recently by Malik and Piepho . However, our literature survey found a correct ratio of 1 in only 10% of the articles, a slightly faulty ratio of the larger scale over the shorter scale within 1.1 in 12%, and a substantially faulty ratio above 2 in 16% with the worst cases being ratios of 31 and 44. Especially when the scale along one PCA axis is stretched by a factor of 2 or more relative to the other axis, the relationships among various points or clusters of points are distorted and easily misinterpreted. Also, 7% of the articles failed to show the scale on one or both PCA axes, which leaves readers with an impressionistic graph that cannot be reproduced without effort. The contemporary literature on PCA of SNP data mostly violates the prohibition against stretching axes.
The percentage of variation captured by each PC is often included in the axis labels of PCA graphs or biplots. In general this information is worth including, but there are two qualifications. First, these percentages need to be interpreted relative to the size of the data matrix because large datasets can capture a small percentage and yet still be effective. For example, for a large dataset with over 107,000 SNPs for over 6,000 persons, the first two components capture only 0.3693% and 0.117% of the variation, and yet the PCA graph shows clear structure (Fig 1A in ). Contrariwise, a PCA graph could capture a large percentage of the total variation, even 50% or more, but that would not guarantee that it will show evident structure in the data. Second, the interpretation of these percentages depends on exactly how the PCA analysis was conducted, as explained in a later section on PCA variants. Readers cannot meaningfully interpret the percentages of variation captured by PCA axes when authors fail to communicate which variant of PCA was used.
Five simple recommendations for effective PCA analysis of SNP data emerge from this investigation.
Use the SNP coding 1 for the rare or minor allele and 0 for the common or major allele.
Use DC-PCA; for any other PCA variant, examine its augmented ANOVA table.
Report which SNP coding and PCA variant were selected, as required by contemporary standards in science for transparency and reproducibility, so that readers can interpret PCA results properly and reproduce PCA analyses reliably.
Produce PCA biplots of both Items and SNPs, rather than merely PCA graphs of only Items, in order to display the joint structure of Items and SNPs and thereby to facilitate causal explanations. Be aware of the arch distortion when interpreting PCA graphs or biplots.
Produce PCA biplots and graphs that have the same scale on every axis.
I read the referenced paper Biplots: Do Not Stretch Them!, by Malik and Piepho (2018), and even though it is not directly applicable to the most commonly available PCA graphs out there, it is a good reminder of the distorting effects of stretching. So for example quite recently in Krause-Kyora et al. (2018), where you can see Corded Ware and BBC samples from Central Europe clustering with samples from Yamna:
NOTE. This is related to a vertical distorsion (i.e. horizontal stretching), but possibly also to the addition of some distant outlier sample/s.
The so-called ‘Yamnaya’ ancestry
Every time I read papers like these, I remember commenters who kept swearing that genetics was the ultimate science that would solve anthropological problems, where unscientific archaeology and linguistics could not. Well, it seems that, like radiocarbon analysis, these promising developing methods need still a lot of refinement to achieve something meaningful, and that they mean nothing without traditional linguistics and archaeology… But we already knew that.
Also, if this is happening in most peer-reviewed publications, made by professional geneticists, in journals of high impact factor, you can only wonder how many more errors and misinterpretations can be found in the obscure market of so many amateur geneticists out there. Because amateur geneticist is a commonly used misnomer for people who are not geneticists (since they don’t have the most basic education in genetics), and some of them are not even ‘amateurs’ (because they are selling the outputs of bioinformatic tools)… It’s like calling healers ‘amateur doctors’.
NOTE. While everyone involved in population genetics is interested in knowing the truth, and we all have our confirmation (and other kinds of) biases, for those who get paid to tell people what they want to hear, and who have sold lots of wrong interpretations already, the incentives of ‘being right’ – and thus getting involved in crooked and paranoid behaviour regarding different interpretations – are as strong as the money they can win or loose by promoting themselves and selling more ‘product’.
As a reminder of how badly these wrong interpretations of genetic results – and the influence of the so-called ‘amateurs’ – can reflect on research groups, yet another turn of the screw by the Copenhagen group, in the oral presentations at Languages and migrations in pre-historic Europe (7-12 Aug 2018), organized by the Copenhagen University. The common theme seems to be that Bell Beaker and thus R1b-L23 subclades do represent a direct expansion from Yamna now, as opposed to being derived from Corded Ware migrants, as they supported before.
NOTE. Yes, the “Yamna → Corded Ware → Únětice / Bell Beaker” migration model is still commonplace in the Copenhagen workgroup. Yes, in 2018. Guus Kroonen had already admitted they were wrong, and it was already changed in the graphic representation accompanying a recent interview to Willerslev. However, since there is still no official retraction by anyone, it seems that each member has to reject the previous model in their own way, and at their own pace. I don’t think we can expect anyone at this point to accept responsibility for their wrong statements.
I love the newly invented arrows of migration from Yamna to the north to distinguish among dialects attributed by them to CWC groups, and the intensive use of materials from Heyd’s publications in the presentation, which means they understand he was right – except for the fact that they are used to support a completely different theory, radically opposed to those defended in Heyd’s model…
Now added to the Copenhagen’s unending proposals of language expansions, some pearls from the oral presentation:
Corded Ware north of the Carpathians of R1a lineages developed Germanic;
R1b borugh [?] Italo-Celtic;
the increase in steppe ancestry on north European Bell Beakers mean that they “were a continuation of the Yamnaya/Corded Ware expansion”;
“Corded Ware groups  stopped their expansion and took over the Bell Beaker package before migrating to England” [yep, it literally says that];
Italo-Celtic expanded to the UK and Iberia with Bell Beakers [I guess that included Lusitanian in Iberia, but not Messapian in Italy; or the opposite; or nothing like that, who knows];
2nd millennium BC Bronze Age Atlantic trade systems expanded Proto-Celtic [yep, trade systems expanded the language]
1st millennium BC expanded Gaulish with La Tène, including a “Gaulish version of Celtic to Ireland/UK” [hmmm, datBritish Gaulish indeed].
You know, because, why the hell not? A logical, stable, consequential, no-nonsense approach to Indo-European migrations, as always.
Also, compare still more invented arrows of migrations, from Mikkel Nørtoft’s Introducing the Homeland Timeline Map, going against Kristiansen’s multiple arrows, and even against the own recent fantasy map series in showing Bell Beakers stem from Yamna instead of CWC (or not, you never truly know what arrows actually mean):
I really, really loved that perennial arrow of migration from Volosovo, ca. 4000-800 BC (3000+ years, no less!), representing Uralic?, like that, without specifics – which is like saying, “somebody from the eastern forest zone, somehow, at some time, expanded something that was not Indo-European to Finland, and we couldn’t care less, except for the fact that they were certainly not R1a“.
This and Kristiansen’s arrows are the most comical invented migration routes of 2018; and that is saying something, given the dozens of similar maps that people publish in forums and blogs each week.
It’s hard to accept that this is a series of presentations made by professional linguists, archaeologists, and geneticists, as stated by the official website, and still harder to imagine that they collaborate within the same professional workgroup, which includes experienced geneticists and academics.
I propose the following video to close future presentations introducing innovative ideas like those above, to help the audience find the appropriate mood:
Nevertheless, since we have very few samples, I think we could still see a clear genetic contribution from Yamna to Corded Ware immigrants in the North Caspian region (from Abashevo, in turn a mix of Fatyanovo/Balanovo and Catacomb/Poltavka cultures) in terms of:
Ancestral components and PCA in new Sintashta-Petrovka, Andronovo, and/or later samples – similar the ‘steppe’ drift seen in Potapovka relative to Sintashta samples, both formed by incoming Corded Ware migrants – ; and
R1b-L23 subclades, either appearing scattered during the Sintashta melting pot (of Abashevo/R1a-Z645 and East Yamna-Poltavka/R1b-Z2103 peoples), or resurging after this period, as we have seen in Pre-Balto-Slavic territory.
A lot of people seem to be looking like crazy since O&M 2018 for some sort of connection between Corded Ware and Yamna migrants in Eastern and Central Europe (wheter in SNP calls of samples published, or among almost forgotten academic papers), either to support the ideas of the 2015 papers – for those who relied on their conclusions and built (even if only mentally) far-fetched migration models around it – , or just because of some sort of absurd continuity theory involving modern R1a-Z645 subclades:
Some (the nostalgic ones?) keep looking for just one sample of R1a-Z645 in Yamna, for the same reason.
NOTE. The situation we have seen with the hundreds of samples from O&M 2018, and with the recent additional Eastern European samples, depict an unexpected absolutely clear-cut distinction in Y-DNA haplogroups between Corded Ware and Yamna/Bell Beaker: I really can’t see how the situation could be more obvious for everyone, so I doubt any further samples will make certain people change their minds. Their hope is, I guess, that just one sample may give some more oxygen to infinite pet theories, as we are still surprisingly seeing even with reactionary R1b autochthonous continuists in Western Europe…
However, looking into the most likely future for the field, what we should be expecting right now is continuity of Yamna ancestry and lineages in early Proto-Indo-Iranian territory. Since we only have a few samples from Sintashta-Petrovka, Potapovka, and Andronovo, I think there might be a sizeable number of R1b-Z2103 subclades in the territory inhabited by those who – no doubt – spread the language into Central Asia.
in the Balkans (e.g. in Vučedol or Makó-Kosihy-Čaka), including Greek and even in historical Armenian territory (potentially including Iran Iron Age sample F38 and Armenia LBA/IA RISE397, although the Mitanni may be a confounding factor here), showing the expansion of Palaeo-Balkan languages;
If we find now, as I expect, genetic continuity of east Yamna in Sintashta -> Andronovo (relative to other late Corded Ware peoples), probably including haplogroup R1b-Z2103 mixed with R1a-Z93 before its further reduction of subclades (e.g. to L657) and expansion during its subsequent spread southward…
Why exactly do we need Corded Ware to explain migrations of Late Indo-European speakers?
In other words: if we had the data we have today in 2015, would we have a need for Corded Ware to explain Indo-European migrations from the steppe? Are some people so blinded by their will to (appear to) be right in their past interpretations that they can’t just let go?
NOTE. On a side note, wouldn’t it be nice for this paper to publish some other R1b-L23 (x2103) sample – maybe even R1b-L51 – in Yamna, Andronovo, or Afanasevo territory, to end both autochthonous continuity theories (of North-Eastern and Western Europe) at the same time?
I really hope someone in David Reich’s team understands this matter, or else they will still identify Corded Ware as the (now probably ‘a’ instead) vector of expansion of Indo-European languages, and some of us will still have fun for another 2 or 3 years with such conclusions, until someone in the lab realizes that ancestry ≠ population ≠ ethnic identification ≠ language.
NOTE. It seems rather dull to read how people are discussing in the Twitterverse conventional constructs like ‘human race‘ as found in Reich’s op-ed in The New York Times, as if such grandiose semantic discussions had any practical meaning, when basic anthropological questions actually relevant for Genomics, like the essential ancestral component ≠ people tenet seem not to be of interest for anyone in the field….
Since our Indo-European demic difusion model (and its consequences for our reconstruction of North-West Indo-European) and this blog are becoming more and more popular each day – judging by the constant growth in visits in the past 6 months or so – , I guess the simplemindedness and predictability of certain geneticists is benefitting traditional anthropology directly, driving more and more amateur geneticists to look for sound academic models to answer the growing inconsistencies of genetic research.
NOTE. I am not saying the rejection of Corded Ware as spreading Indo-European is definitive. Maybe more samples within some years will depict a clear ancient expansion of Early or Middle Proto-Indo-Europeans from Khvalynsk to the forest-steppe and forest zone, and later with certain Corded Ware migrants into Central Europe, over whose territory a Late Indo-European dialect from Bell Beakers became the superstrate, as some have proposed in the past – e.g. to explain Krahe’s Old European hydronymy. I really doubt you could demonstrate such an old ethnolinguistic identification with a clear, unbroken archaeological trail, though, and we know now that this old hydronymy is probably of Late Indo-European nature (possibly even more recent).
What I am saying is: with the data we have now, it does not make any sense to keep the anthropological models invented by geneticists ex nihiloin 2015, and the hundred different alternative Late Indo-European migration models that are – born – with – each – new – paper.
These Yamna -> Corded Ware migration models didn’t have any sense for me since early 2016, but now after O&M 2017, and especially O&M 2018, I don’t think any geneticist with a little knowledge in Linguistics or Archaeology (if they are decent about their quest for truth in describing ancient European migrations) would buy them, if not for some sort of created ‘tradition’. So let’s ditch Corded Ware as Late Indo-European-speaking, let’s accept that late Corded Ware migrants should most likely be identified as early Uralic speakers, and then future data will tell if we are – again – wrong.
Please, don’t let Genomics become another pseudoscience based solely on Bioinformatics like glottochronology: let anthropologists (preferably mainstream archaeologists, but also the true Indo-Europeanists, linguists) help you interpret your raw data. Don’t deceive yourselves thinking that you have read enough about the Indo-European question, or that you know enough Indo-Europeanists (say what?) to derive your own conclusions.
Use the South Asia paper to begin expressly retracting the Corded Ware mess.
It happens so that the discussion has turned lately mainly to ancient Y-DNA haplogroups, because they help confirm previous mainstream anthropological models of cultural diffusion and migration. It is obviously not reasonable to judge prehistoric ethnolinguistic migrations from ca. 5,000 years ago based on historical nation-states and ethnic or religious concepts invented since the Middle Ages, coupled with “your” people’s main modern (or your own) paternal lineage.
EDIT (27 MAR 2018): Minor corrections and post made shorter.
As expected, the first Y-DNA haplogroup of a sample from the North Pontic region (apart from an indigenous European I2 subclade) during its domination by the Yamna culture is of haplogroup R1b-L23, and it is dated ca. 2890-2696 BC. More specifically, it is of Z2103 subclade, the main lineage found to date in Yamna samples. The site in question is Dereivka, “in the southern part of the middle Dnieper, at the boundary between the forest-steppe and the steppe zones”.
There is no data on this individual in the supplementary material – since Eneolithic Dereivka samples come from stored dental remains – , but the radiocarbon date (if correct) is unequivocal: the Yamna cultural-historical community dominated over that region at that precise time. Why would the authors name it just “Ukraine_Eneolithic”? They surely took the assessment of archaeologists, and there is no data on it, so I agree this is the safest name to use for a serious paper. This would not be the first sample apparently too early for a certain culture (e.g. Catacomb in this case) which ends up being nevertheless classified as such. And it is also not impossible that it represents another close Ukraine Eneolithic culture, since ancestral cultural groups did not have borders…
NOTE. Why, on the other hand, was the sample from Zvejnieki – classified as of Latvia_LN – assumed to correspond to “Corded Ware” (like the recent samples from Plinkaigalis242 or Gyvakarai1), when we don’t have data on their cultures either? No conspiracy here, just taking assessments from different archaeologists in charge of these samples: those attributed to “Corded Ware” have been equally judged solely by radiocarbon date, but, combining the known archaeological signs of herding in the region arriving around this time with the old belief (similar to the “Iberia is the origin of Bell Beaker peoples” meme) that “only the Corded Ware culture signals the arrival of herding in the Baltic”. This assumption has been contested recently by Furholt, in an anthropological model that is now mainstream, upheld also by Anthony.
We already know that, out of three previous West Yamna samples, one shows Anatolian Neolithic ancestry, the so-called “Yamna outlier”. We also know that one sample from Yamna in Bulgaria also shows Anatolian Neolithic ancestry, with a distinct ‘southern’ drift, clustering closely to East Bell Beaker samples, as we can still see in Mathieson et al. (2018), see below. So, two “outliers” (relative to East Yamna samples) out of four samples… Now a new, fifth sample from Ukraine is another “outlier”, coinciding with (and possibly somehow late to be a part of) the massive migration waves into Central Europe and the Balkans predicted long ago by academics and now confirmed with Genomics.
I think there are two good explanations right now for its ancestral components and position in PCA:
How many generations are needed for ancestral components and PCA clusters to change to that extent, in regions where only some patrilocal chiefs but indigenous populations remain, and the population probably admixed due to exogamy, back-migrations, and “resurge” events? Not many, obviously, as we see from the differences among the many Bell Beaker samples of R1b-L23 subclades from Olalde et al. (2018)…
b) That this sample shows the first genetic sign of the precise population that contributed to the formation of the Catacomb culture. Since it is a hotly debated topic where and how this culture actually formed to gradually replace the Yamna culture in the central region of the Pontic-Caspian steppe, this sample would be a good hint of how its population came to be.
This could then be not ‘just another West Yamna outlier’, but would actually show meaningful ‘resurge’ of Neolithic Ukraine ancestry in the Catacomb culture.
It could be meaningul to derive hypotheses, in the same way that the late Central European CWC sample from Esperstedt (of R1a-M417 subclade) shows recent exogamy directly from the (now more probably eastern part of the) steppe or steppe-forest, and thus implies great mobility among distant CWC groups. Although, given the BB samples with elevated steppe ancestry and close PCA cluster from Olalde et al. (2018), it could also just mean exogamy from a near-by region, around the Carpathian Basin where Yamna migrants settled…
How to know which is the case? We have to wait for more samples in the region. For the moment, the date seems too early for the known radiocarbon dating of most archaeological remains of the Catacomb Culture.
An important consequence of the addition of these “Yamna outliers” for the future of research on Indo-European migrations is that, especially if confirmed as just another West Yamna sample – with more, similar samples – , early Palaeo-Balkan peoples migrating south of the Danube and later through Anatolia may need to be judged not only in terms of ancestral components or PCA (as in the paper on Minoans and Mycenaeans), but also and more decisively using phylogeography, especially with the earliest samples potentially connected with such migrations.
Even without express confirmation of its presence in the steppe, the alternative model of a Balkan origin seems unlikely, given the almost certain continuity of expanding Yamna clans as East Bell Beaker ones, in this clearly massive and relatively quick expansion that did not leave much time for founder effects. But, of course, it is not impossible to think about a previously hidden R1b-L151 community in the Carpathian Basin yet to be discovered, adopting North-West Indo-European (by some sort of founder effect) brought there by Yamna peoples of exclusively R1b-Z2103 lineages. As it is not impossible to think about a hidden and ‘magically’ isolated community of haplogroup R1a-M417 in Yamna waiting to be discovered…Just not very likely, either option.
As to why this sample or the other Bell Beaker samples “solve” the question of R1a-Z645 subclades (typical of Corded Ware migrants) not expanding with Yamna, it’s very simple: it doesn’t. What should have settled that question – in previous papers, at least since 2015 – is the absence of this subclade in elite chiefs of clans expanded from Khvalynsk, Yamna, or their only known offshoots Afanasevo and Bell Beaker. Now we only have still more proof, and no single ‘outlier’ in that respect.
Not that radiocarbon dates or the actual origin of this sample cannot be wrong, mind you, it just strikes me how twisted such biased reasonings may be, depending on the specific sample at hand… Denial, anger, and bargaining, including shameless circular reasoning – we know the drill: we have seen it a hundred times already, with all kinds of supremacists autochthonous continuists who still today manage to place an oudated mythical symbolism on expanding Proto-Indo-Europeans, or on regional ethnolinguistic continuity…
Beginning with the new year, I wanted to commit myself to some predictions, as I did last year, even though they constantly change with new data.
I recently read Proto-Indo-European homelands – ancient genetic clues at last?, by Edward Pegler, which is a good summary of the current state of the art in the Indo-European question for many geneticists – and thus a great example of how well Genetics can influence Indo-European studies, and how badly it can be used to interpret actual cultural events – although more time is necessary for some to realize it. Notice for example the distribution of ‘Yamnaya’ in 3000 BC, all the way to Latvia (based on the initial findings of Mathieson et al. 2017), and the map of 2000 BC with ‘Corded Ware’, both suggesting communities linked by admixture and unrelated to actual cultures.
Some people – especially those interested in keeping a simplistic picture of Europe, either divided into admixture groups or simplistic R1b-Vasconic / R1a-Indo-European / N1c-Uralic (or any combination thereof) – want (others) to believe that I am linking ‘Indo-Europeans’ with haplogroup R1b. That is simply not true. In fact, my model dismisses such simplistic identifications of the reconstructible proto-languages with any modern peoples, admixtures, or haplogroups.
The beauty of the model lies, therefore, precisely in that if you take any modern group speaking Indo-European languages, none can trace back their combination of language, admixture, and/or haplogroup to a common Indo-European-speaking people. All our ancestral lines have no doubt changed language families (and indeed cultures), they have admixed, and our European regions’ paternal lines have changed, so that any dreams of ‘purity’ or linguistic/cultural/regional continuity become absurd.
That conclusion, which should be obvious to all, has been denied for a long time in blogs and forums alike, and is behind the effort of many of those involved in amateur genetics.
Main linguistic aim
The main consequence of the model, as the title of the paper suggests, is that reconstructible Indo-European proto-languages expanded with people, i.e. with actual communities, which is what we can assert with the help of Genomics. From a personal (or ethnic, or political) point of view genomics is useless, but from an anthropological (and thus linguistic) point of view, genomics can be a very useful tool to decide between alternative models of language diffusion, which has given lots of headaches to those of us involved in Indo-European studies.
The demic diffusion theory for the three main stages of the proto-language expansion was originally, therefore, a dismissal of impossible-to-prove cultural diffusion models for the proto-language – e.g. the adoption of Late Proto-Indo-European by Corded Ware groups due to a patron-client relationship (as proposed by Anthony), or a long-lasting connection between cultures (as proposed by Kristiansen, and favoured by “constellation analogy” proponents like Clackson, who negated the existence of common proto-languages). It also means the acceptance of the easiest anthropological model for language change: migration and – consequently – replacement.
Before the famous 2015 papers (and even after them, if we followed their interpretation), we were left to wonder why the supposed vector of expansion of Indo-European languages, Corded Ware migrants – represented by R1a-Z645 subclades, and supposedly continued unchanged into modern populations in its ‘original’ ancestral territories, Balto-Slavic and Indo-Iranian – , were precisely the (phonetically) most divergent Indo-European languages – relative to the parent Late Indo-European proto-language.
My paper implied therefore the dismissal of an unlikely Indo-Slavonic group, as proposed by Kortlandt, and of a still less factible Germano-Slavonic, or Germano-Indo-Slavonic (?) group, as loosely implied by some in the past, and maybe supported in certain archaeological models (viz. Kristiansen or partially Anthony), and presently by some geneticists since their simplistic 2015 papers on “massive migrations from the steppe“, and amateur genetic fans with infinite pet theories, indeed.
A common Corded Ware substrate to Balto-Slavic and Indo-Iranian, and common also partially between Balto-Slavic and Germanic (as supported by Kortlandt, too, albeit with different linguistic connotations), would explain their common features. The Corded Ware culture (and Uralic, tentatively proposed by me as the group’s main language family) is a strong potential connection between them, further supported by phylogeography, too.
Interpretations in my paper help thus dismiss the simplistic Yamna -> Corded Ware -> Bell Beaker migration model implied with phylogeography in the 2000s, and revived again by geneticists and Kristiansen’s workgroup based on the famous 2015 papers, whereby – due to the “Yamnaya ancestral component” – the Yamna culture would have been composed of communities of R1a-M417 and R1b-M269 lineages which remained against all odds ‘related but separated’ for more than two thousand years, sharing a common unitary language (why? and how?), and which expanded from Yamna (mainly R1b-L23) into Corded Ware (mainly R1a-M417) and then into Bell Beaker (mainly R1b-L51), in imaginary migration waves whose traces Archaeology has not found, or Anthropology described, before.
While phylogeography (especially the distribution of ancient samples of certain R1b and R1a subclades) was the main genetic aspect I used in combination with Archaeology and Anthropology to challenge the reliability of the “Yamnaya ancestral component” in assessing migrations – and thus Kristiansen’s now-popular-again modified Kurgan model – , my main aim was to prove a recent expansion of Late Proto-Indo-European from the steppe, and a still more recent expansion of a common group of speakers of North-West Indo-European, the language ancestral to Italo-Celtic, Germanic, and probably Balto-Slavic (or ‘Temematic’, the NWIE substrate of Balto-Slavic, according to some linguists).
My arguments serve for this purpose, and modern distributions of haplogroups or admixture are fully irrelevant: I am ready to change my view at any time, regarding the role of any haplogroup, or ancestral component, archaeological data, or anthropological migration model, to the extent that it supports the soundest linguistic model.
Gimbutas’ old theory of sudden and recent expansion served well to support a real community of Proto-Indo-European speakers, as did later the Yamna -> Corded Ware -> Bell Beaker theory that circulated in the 2000s based on modern phylogeography, and as did later partially Anthony’s updated steppe theory (2007). On the other hand, Kristiansen’s long-lasting connections among north-west Pontic steppe cultures and Globular Amphorae and Trypillian cultures, did not fit well with a close community expanding rapidly – although recent genetic data on Trypillia and Globular Amphorae might be compelling him to improve his migration theory.
So, if data turns out to be not as I expect now, I will reflect that in future versions of the paper. I have no problem saying I am wrong. I have been wrong many times before, and something I am certain is that I am wrong now in many details, and I am going to be in the future.
If, for example, R1b-L23(xZ2105) is demonstrated to come from Hungary and not the steppe (as supported by Balanovsky) or R1a-M417 samples are proved to have expanded with West Yamna settlers (as recently proposed by Anthony, see below the Balto-Slavic question), I would support the same model from a linguistic point of view, but modified to reflect these facts. Or if a direct migration link is found in Archaeology from Yamna to Corded Ware, and from Corded Ware to Bell Beaker (as proposed in the 2015 papers), I will revise that too (again, see the image below). Or, if – as Lazaridis et al. (2017) paper on Minoans and Mycenaeans suggested – the Anatolian hypothesis (that is, one of the multiple ones proposed) turns out to be somehow right, I will support it.
Haplogroups are the least important aspect of the whole model, they are just another data that has to be taken into account for a throrough explanation of migrations. It has become essential today because of the apparent lack of vision on the part of geneticists, who failed to use them to adjust their findings of admixture with findings of haplogroup expansions, favouring thus a marginal theory of long-lasting steppe expansion instead of the mainstream anthropological models.
Since many of these alternative scenarios seem less and less likely with each new paper, it is probably more efficient to talk about which developments are most likely to challenge my model.
My main predictions – based mostly on language guesstimates, archaeological cultures, and anthropological models of migration -, even with the scarce genomic data we had, have been proven right until know with new samples from Mathieson et al. (2017) and Olalde et al. (2017), among other papers of this past year. These were my original assumptions:
(1) A Middle Proto-Indo-European expansion defined by the appearance of steppe ancestry + reduction in haplogroup diversity and expansion of (mainly) R1b-M269 and R1b-L23 lineages;
The expansion of Corded Ware peoples, associated with steppe ancestry + reduction in haplogroup diversity and expansion of (mainly) R1a-Z645 subclades, represents thus a different migration, which is compatible with the different nature of the Corded Ware culture, unrelated to Yamna and without migration waves from one to the other (although there were certainly contacts in neighbouring regions).
As you can see, neither of the 3+1 expansion models imply that no other haplogroup can be found in the culture or regions involved (others have in fact been found, and still the models remain valid): these migrations imply a reduction of haplogroup diversity, and the expansion of certain subclades as is common in population expansions throughout history. While we all accept this general idea, some people have difficulties accepting just those cases not compatible with their dreams of autochthonous continuity.
Nevertheless, there are still voids in genetic investigation.
In my humble opinion, these are potential conflict periods and the most likely areas of change for the future of the theory:
1. When and how did R1b-M269 lineages become “chiefs” in the steppe?
Based on scarce data from Khvalynsk, it seems that during the Neolithic there were many haplogroups in the North Pontic and North Caspian steppes. A reduction to R1b-M269 subclades must have happened either just before or (as I support) during (the migrations that caused) the Suvorovo-Novodanilovka expansion among Sredni Stog, probably coinciding also with the expansion (or one of the expansions) of CHG ancestry (and thus the appearance of ‘Steppe component’ in the steppe). My theory was based initially on Anthony’s account and TMRCA of haplogroups of modern populations (both ca. 4200-4000 BC), but recent samples of the Balkans (R1b-M269 and steppe ancestry) seem to trace the population expansion some centuries back.
If my assessment is correct, then modern populations of haplogroup R1b-M269* and R1b-L23* in the Balkans probably reflect that ancient expansion, and samples related to Proto-Anatolian cultures in the Balkans will most likely be of R1b-M269 subclades and R1b-L23*. After admixture in the Balkans, posterior migrations of Anatolian languages into Anatolia might be associated with a different admixture component and haplogroups, we don’t have enough data yet.
If the haplogroup reduction and expansion in Khvalynsk happened later than the Suvorovo-Novodanilovka expansion, then we might find the expansion of Pre- or Proto-Anatolian associated with many different haplogroups, such as R1b (xM269), R1a, I, J, or G2, and more or less associated with steppe ancestry in the Balkans.
Another reason for finding such variety of haplogroups in ancient samples from the Balkans would be that this Khvalynsk group of “chiefs” traversed – and mixed with – the Sredni Stog population. Nevertheless, if we suppose homogeneity in haplogroups in Khvalynsk during the expansion, a high proportion of different haplogroups explained by admixture with the local population of Sredni Stog would challenge the whole “chief domination” explanation by Anthony, and we would have to return to the “different culture” theory by Rassamakin and potentially an older migration from Khvalynsk. In any case, both researchers show clear links of the Suvorovo-Novodanilovka phenomenon to Khvalynsk, and a differentiation with the surrounding Sredni Stog culture.
A less likely model would support the identification of the whole Eneolithic Pontic-Caspian steppe as a loose Indo-Hittite-speaking community, which would be in my opinion too big a territory and too loose a cultural bond to justify such a long-lasting close linguistic connection. This will probably be the refuge of certain people looking desperately for R1a-IE connections. However, the nature of the western steppe will remain distinct from Late Proto-Indo-European, which must have developed in the Yamna culture, so autochthonous continuity is not on the table anymore, in any case…
2. How did R1a-M417 (and especially R1a-Z645) haplogroups came to dominate over the Corded Ware cultures?
If I am right (again, based on TMRCA of modern populations), then it is precisely at the time of the potential expansion of Proto-Corded Ware from the Dnieper-Dniester forest, forest-steppe, and steppe regions, ca 3300-3000. Furholt’s recent radiocarbon analysis and suggestions of a Lesser Poland origin of the third or A-horizon, on which disparate archaeologists such as Anthony or Klejn rely now, seem to suggest also that Corded Ware was a cultural complex rather than a compact culture reflecting a migration of peoples – similar thus to the Bell Beaker complex.
This cultural complex interpretation of Corded Ware contrasts with the quite homogeneous late samples we have, suggesting clear migration waves in northern Europe, at least at some point in time, so Genomics will be a great tool to ascertain when and from where approximately did Corded Ware peoples expand. Right now, it seems that Eneolithic Ukraine populations are the closest to its origin, so the traditional interpretation of its regional origin by Kristiansen or Anthony remains valid.
3. How was Indo-Iranian adopted by Corded Ware invaders?
As for what some Indians – and other people willing to confront them – are looking for, regarding R1a-M417 and/or Indo-European origins in India, I don’t see the point, we already know a) that the origin of the expansion is in the steppe and b) that Hindu nationalist biggots will not accept results from research that oppose their views. I don’t expect huge surprises there, just more fruitless discussions (fomented by those who live from trolling or conspiracies)…
4. Yamna settlers from Hungary
Anthony’s new theory – and the nature of Balto-Slavic – hinges on the presence of R1a-M417 subclades (associated with later Corded Ware samples) in Yamna settlers of Hungary, potentially originally from the North Pontic area, where the oldest sample has been found.
My ‘modified’ version of Anthony’s new model (the only I deem just remotely factible) includes the expansion of a Proto-Corded Ware from Lesser Poland, but (given the overwhelming R1b found in East Bell Beaker), with R1a-M417 being associated with the region. How to explain this language change with objective data? Well, we have Bell Beaker expanding to these areas at a later time, so we would need to find R1b-L23 settlers in Lesser Poland, and then a resurge of R1a-M417 haplogroup. If not, resorting yet again to cultural diffusion Yamna “patrons” to Corded Ware “clients” of Lesser Poland would bring us to square one, now with the ‘steppe ancestry’ controversy included…
Since some Eastern Europeans are (for no obvious reason whatsoever) putting their hopes on that IE-R1a-CWC association, let’s hope some samples of R1a-M417 in Yamna or Hungary give them a break, so that they can begin accepting something closer to mainstream anthropological models. We could then work from there a Yamna-> Bell Beaker / North-West Indo-European association truce, and from there keep accepting that no single haplogroup from Yamna settlers is linked with modern languages, cultures or ethnic groups.
5. How and when was Balto-Slavic associated with haplogroup R1a?
On the other hand, if it is a Northern dialect related closely to Germanic and Italo-Celtic (in a North-West Indo-European group), then its origin has to be found in the initial expansion of East Bell Beakers, and its development into either the Únětice culture (of Balkan and thus potentially “Southern IE” influence), or the Mierzanowice-Nitra culture (of Corded Ware and thus potentially Uralic influence), or maybe from both, given the intermediate substrate found in Germanic and Balto-Slavic.
It is my opinion that the association of Balto-Slavic with haplogroup R1a is quite early after the East Bell Beaker expansion, probably initially with the subclade typically associated with West Slavic, R1a-M458. I have not much data to support this (apart from the most common linguistic model), just modern haplogroup distribution maps and common TMRCA, and highly hypothetical archaeological-anthropological models. Genetics will hopefully bring more data.
Let’s see also what information on ancient haplogroups we can obtain from the Tollense valley (already showing a close cluster with modern West Slavic populations) and steppe regions.
The expansion of Celtic seems to be associated with chiefdoms, untraceable today in terms of haplogroups, and it seems thus different from previous expansions. New studies might tell how that happened, if it was actually in successive ways, as proposed, or maybe we don’t have enough data yet to reach conclusions.
We don’t know either how Italic expanded into the Italian Peninsula, or whether Latin expanded with peoples from Italy, if at all, or it was mostly a cultural diffusion event, as it seems.
Regarding Etruscan, while I think it is a controversy initiated based on fantastic accounts, and ignited with few finds of Middle Eastern ancestry (that seem logical from the point of view of regional contacts), it will be important for Italian linguists and archaeologists, also to accept the most likely scenario.
NOTE: Although mostly unrelated, linguistic questions may also be somehow altered with a change of migration models. For example, our current Corded Ware Substrate Hypothesis – strongly contested by Kortlandt and others – implies that Uralic was potentially the language spoken by Eneolithic Ukraine / Proto-Corded Ware peoples, therefore early Uralic languages were spoken by Corded Ware peoples, as a substrate for Germanic and Balto-Slavic, and Balto-Slavic and Indo-Iranian. If an Indo-Hittite branch different from Late PIE is accepted for Eneolithic Ukraine (thus suggesting a millennia-long cultural-historical community in the steppe), then the model still stands (e.g. Ger. and BSl. *-mos/-mus, as stated by Kortlandt, would correspond to the oldest morphological IE layer). As you can read in the different versions of our model, the different possibilities for the common substrate are stated, and the most likely one selected. But the most likely a priori option sometimes turns out to be wrong…
NOTE 2: You can comment whatever you want here, but I opened a specific thread in our forum if you want serious comments on the model to stuck and be further discussed.