Evolution of Steppe, Neolithic, and Siberian ancestry in Eurasia (ISBA 8, 19th Sep)

jena-isba8

Some information is already available from ISBA 8 (see programme in PDF), thanks to the tweets from Alexander M. Kim.

Official abstracts are listed first (emphasis mine), then reports and images with link to Kim’s tweets. Here is the list for quick access:

Updates (17:00 CET):

Turkic and Hunnic expansions

Tracing the origin and expansion of the Turkic and Hunnic confederations, by Flegontov et al.

Turkic-speaking populations, now spread over a vast area in Asia, are highly heterogeneous genetically. The first confederation unequivocally attributed to them was established by the Göktürks in the 6th c. CE. Notwithstanding written resources from neighboring sedentary societies such as Chinese, Persian, Indian and Eastern Roman, earlier history of the Turkic speakers remains debatable, including their potential connections to the Xiongnu and Huns, which dominated the Eurasian steppe in the first half of the 1st millennium CE. To answer these questions, we co-analyzed newly generated human genome-wide data from Central Asia (the 1240K panel), spanning the period from ca. 3000 to 500 YBP, and the data published by de Barros Damgaard et al. (137 ancient human genomes from across the Eurasian steppes, Nature, 2018). Firstly, we generated a PCA projection to understand genetic affinities of ancient individuals with respect to present-day Tungusic, Mongolic, Turkic, Uralic, and Yeniseian-speaking groups. Secondly, we modeled hundreds of present-day and few ancient Turkic individuals using the qpAdm tool, testing various modern/ancient Siberian and ancient West Eurasian proxies for ancestry sources.

A majority of Turkic speakers in Central Asia, Siberia and further to the west share the same ancestry profile, being a mixture of Tungusic or Mongolic speakers and genetically West Eurasian populations of Central Asia in the early 1st millennium CE. The latter are themselves modelled as a mixture of Iron Age nomads (western Scythians or Sarmatians) and ancient Caucasians or Iranian farmers. For some Turkic groups in the Urals and the Altai regions and in the Volga basin, a different admixture model fits the data: the same West Eurasian source + Uralic- or Yeniseian-speaking Siberians. Thus, we have revealed an admixture cline between Scythians and the Iranian farmer genetic cluster, and two further clines connecting the former cline to distinct ancestry sources in Siberia. Interestingly, few Wusun-period individuals harbor substantial Uralic/Yeniseian-related Siberian ancestry, in contrast to preceding Scythians and later Turkic groups characterized by the Tungusic/Mongolic-related ancestry. It remains to be elucidated whether this genetic influx reflects contacts with the Xiongnu confederacy. We are currently assembling a collection of samples across the Eurasian steppe for a detailed genetic investigation of the Hunnic confederacies.

jeong-population-clines
Three distinct East/West Eurasian clines across the continent with some interesting linguistic correlates, as earlier reported by Jeong et al. (2018). Alexander M. Kim.
siberian-genetic-component-chronology
Very important observation with implication of population turnover is that pre-Turkic Inner Eurasian populations’ Siberian ancestry appears predominantly “Uralic-Yeniseian” in contrast to later dominance of “Tungusic-Mongolic” sort (which does sporadically occur earlier). Alexander M. Kim

New interesting information on the gradual arrival of the “Uralic-Yeniseian” (Siberian) ancestry in eastern Europe with Iranian and Turkic-speaking peoples. We already knew that Siberian ancestry shows no original relationship with Uralic-speaking peoples, so to keep finding groups who expanded this ancestry eastwards in North Eurasia should be no surprise for anyone at this point.

Central Asia and Indo-Iranian

The session The Genomic Formation of South and Central Asia, by David Reich, on the recent paper by Narasimhan et al. (2018).

bmac-reich
One important upside of dense genomic sampling at single localities – greater visibility of outliers and better constraints on particular incoming ancestries’ arrival times. Gonur Tepe as a great case study of this. Alexander M. Kim
ani-asi-steppe-cline
– Tale of three clines, with clear indication that “Indus Periphery” samples drawn from an already-cosmopolitan and heterogeneous world of variable ASI & Iranian ancestry. (I know how some people like to pore over these pictures – so note red dots = just dummy data for illustration.)
– Some more certainty about primary window of steppe ancestry injection into S. Asia: 2000-1500 BC
Alexander M. Kim

British Isles

Ancient DNA and the peopling of the British Isles – pattern and process of the Neolithic transition, by Brace et al.

Over recent years, DNA projects on ancient humans have flourished and large genomic-scale datasets have been generated from across the globe. Here, the focus will be on the British Isles and applying aDNA to address the relative roles of migration, admixture and acculturation, with a specific focus on the transition from a Mesolithic hunter-gatherer society to the Neolithic and farming. Neolithic cultures first appear in Britain ca. 6000 years ago (kBP), a millennium after they appear in adjacent areas of northwestern continental Europe. However, in Britain, at the margins of the expansion the pattern and process of the British Neolithic transition remains unclear. To examine this we present genome-wide data from British Mesolithic and Neolithic individuals spanning the Neolithic transition. These data indicate population continuity through the British Mesolithic but discontinuity after the Neolithic transition, c.6000 BP. These results provide overwhelming support for agriculture being introduced to Britain primarily by incoming continental farmers, with surprisingly little evidence for local admixture. We find genetic affinity between British and Iberian Neolithic populations indicating that British Neolithic people derived much of their ancestry from Anatolian farmers who originally followed the Mediterranean route of dispersal and likely entered Britain from northwestern mainland Europe.

british-isles
Millennium of lag between farming establishment in NW mainland Europe & British Isles. Only 25 Mesolithic human finds from Britain. Alexander M. Kim.
british-admixture
– Evidently no resurgence of hunter-gatherer ancestry across Neolithic
– Argument for at least two geographically distinct entries of Neolithic farmers
Alexander M. Kim.

MN Atlantic / Megalithic cultures

Genomics of Middle Neolithic farmers at the fringe of Europe, by Sánchez Quinto et al.

Agriculture emerged in the Fertile Crescent around 11,000 years before present (BP) and then spread, reaching central Europe some 7,500 years ago (ya.) and eventually Scandinavia by 6,000 ya. Recent paleogenomic studies have shown that the spread of agriculture from the Fertile Crescent into Europe was due mainly to a demic process. Such event reshaped the genetic makeup of European populations since incoming farmers displaced and admixed with local hunter-gatherers. The Middle Neolithic period in Europe is characterized by such interaction, and this is a time where a resurgence of hunter-gatherer ancestry has been documented. While most research has been focused on the genetic origin and admixture dynamics with hunter-gatherers of farmers from Central Europe, the Iberian Peninsula, and Anatolia, data from farmers at the North-Western edges of Europe remains scarce. Here, we investigate genetic data from the Middle Neolithic from Ireland, Scotland, and Scandinavia and compare it to genomic data from hunter-gatherers, Early and Middle Neolithic farmers across Europe. We note affinities between the British Isles and Iberia, confirming previous reports. However, we add on to this subject by suggesting a regional origin for the Iberian farmers that putatively migrated to the British Isles. Moreover, we note some indications of particular interactions between Middle Neolithic Farmers of the British Isles and Scandinavia. Finally, our data together with that of previous publications allow us to achieve a better understanding of the interactions between farmers and hunter-gatherers at the northwestern fringe of Europe.

megalithic-europe
-Novel genomic data from 21 individuals from 6 sites.
– “Megalithic” individuals not systematically diff. from geographically proximate “non-megalithic” burials
– Mild evidence for over-representation of males in some British Isles megalithic tombs
– Megalithic tombs in W & N Neolithic Europe may have link to kindred structures
Alexander M. Kim

Central European Bronze Age

Ancient genomes from the Lech Valley, Bavaria, suggest socially stratified households in the European Bronze Age, by Mittnik et al.

Archaeogenetic research has so far focused on supra-regional and long-term genetic developments in Central Europe, especially during the third millennium BC. However, detailed high-resolution studies of population dynamics in a microregional context can provide valuable insights into the social structure of prehistoric societies and the modes of cultural transition.

Here, we present the genomic analysis of 102 individuals from the Lech valley in southern Bavaria, Germany, which offers ideal conditions for such a study. Several burial sites containing rich archaeological material were directly dated to the second half of the 3rd and first half of the 2nd millennium BCE and were associated with the Final Neolithic Bell Beaker Complex and the Early and Middle Bronze Age. Strontium isotope data show that the inhabitants followed a strictly patrilocal residential system. We demonstrate the impact of the population movement that originated in the Pontic-Caspian steppe in the 3rd millennium BCE and subsequent local developments. Utilising relatedness inference methods developed for low-coverage modern DNA we reconstruct farmstead related pedigrees and find a strong association between relatedness and grave goods suggesting that social status is passed down within families. The co-presence of biologically related and unrelated individuals in every farmstead implies a socially stratified complex household in the Central European Bronze Age.

lech-bavaria
Diminishing steppe ancestry and resurgent Neolithic ancestry over time. Alexander M. Kim

Notice how the arrival of Bell Beakers, obviously derived from Yamna settlers in Hungary, and thus clearly identified as expanding North-West Indo-Europeans all over Europe, marks a decrease in steppe ancestry compared to Corded Ware groups, in a site quite close to the most likely East BBC homeland. Copenhagen’s steppe ancestry = Indo-European going down the toilet, step by step…

UPDATES

Russian Far East populations

Gene geography of the Russian Far East populations – faces, genome-wide profiles, and Y-chromosomes, by Balanovsky et al.

Russian Far East is not only a remote area of Eurasia but also a link of the chain of Pacific coast regions, spanning from East Asia to Americas, and many prehistoric migrations are known along this chain. The Russian Far East is populated by numerous indigenous groups, speaking Tungusic, Turkic, Chukotko-Kamchatka, Eskimo-Aleut, and isolated languages. This linguistic and geographic variation opens question about the patterns of genetic variation in the region, which was significantly undersampled and received minor attention in the genetic literature to date. To fill in this gap we sampled Aleuts, Evenks, Evens, Itelmens, Kamchadals, Koryaks, Nanais, Negidals, Nivkhs, Orochi, Udegeis, Ulchi, and Yakuts. We also collected the demographic information of local populations, took physical anthropological photos, and measured the skin color. The photos resulted in the “synthetic portraits” of many studied groups, visualizing the main features of their faces.

north-eurasia

far-east-pca
Impressive North Eurasian biobank including 30,500 individual samples with broad consent, some genealogical info, phenotypic data. Alexander M. Kim

Finland AD 5th-8th c.

Sadly, no information will be shared on the session A 1400-year transect of ancient DNA reveals recent genetic changes in the Finnish population, by Salmela et al. We will have to stick to the abstract:

Objectives: Our objective was to use aDNA to study the population history of Finland. For this aim, we sampled and sequenced 35 individuals from ten archaeological sites across southern Finland, representing a time transect from 5th to 18th century.

Methods: Following genomic DNA extraction and preparation of indexed libraries, the samples were enriched for 1,2 million genomewide SNPs using in-solution capture and sequenced on an Illumina HighSeq 4000 instrument. The sequence data were then compared to other ancient populations as well as modern Finns, their geographical neighbors and worldwide populations. Authenticity testing of the data as well as population history inference were based on standard computational methods for aDNA, such as principal component analysis and F statistics.

Results: Despite the relatively limited temporal depth of our sample set, we are able to see major genetic changes in the area, from the earliest sampled individuals – who closely resemble the present-day Saami population residing markedly further north – to the more recent ancient individuals who show increased affinity to the neighboring Circum-Baltic populations. Furthermore, the transition to the present-day population seems to involve yet another perturbation of the gene pool.

So, most likely then, in my opinion – although possibly Y-DNA will not be reported – Finns were in the Classical Antiquity period mostly R1a with secondary N1c in the Circum-Baltic region (similar to modern Estonians, as I wrote recently), while Saami were probably mostly a mix of R1a-Z282 and I1 in southern Finland. That’s what the first transition after the 5th c. probably reflects, the spread of Finns (with mainly N1c lineages) to the north, while the more recent transition shows probably the introduction of North Germanic ancestry (and thus also R1b-U106, R1a-Z284, and I1 lineages) in the west.

Dairying in ancient Mongolia

The History of Dairying in ancient Mongolia, by Wilkin et al.

The use of mass spectrometry based proteomics presents a novel method for investigating human dietary intake and subsistence strategies from archaeological materials. Studies of ancient proteins extracted from dental calculus, as well as other archaeological material, have robustly identified both animal and plant-based dietary components. Here we present a recent case study using shotgun proteomics to explore the range and diversity of dairying in the ancient eastern Eurasian steppe. Contemporary and prehistoric Mongolian populations are highly mobile and the ephemerality of temporarily occupied sites, combined with the severe wind deflation common across the steppes, means detecting evidence of subsistence can be challenging. To examine the time depth and geographic range of dairy use in Mongolia, proteins were extracted from ancient dental calculus from 32 individuals spanning burial sites across the country between the Neolithic and Mongol Empire. Our results provide direct evidence of early ruminant milk consumption across multiple time periods, as well as a dramatic increase in the consumption of horse milk in the late Bronze Age. These data provide evidence that dairy foods from multiple species were a key part of subsistence strategies in prehistoric Mongolia and add to our understanding of the importance of early pastoralism across the steppe.

The confirmation of the date 3000-2700 BC for dairying in the eastern steppe further supports what was already known thanks to archaeological remains, that the pastoralist subsistence economy was brought for the first time to the Altai region by expanding late Khvalynsk/Repin – Early Yamna pastoralists that gave rise to the Afanasevo culture.

Neolithic transition in Northeast Asia

Genomic insight into the Neolithic transition peopling of Northeast Asia, by C. Ning

East Asian representing a large geographic region where around one fifth of the world populations live, has been an interesting place for population genetic studies. In contrast to Western Eurasia, East Asia has so far received little attention despite agriculture here evolved differently from elsewhere around the globe. To date, only very limited genomic studies from East Asia had been published, the genetic history of East Asia is still largely unknown. In this study, we shotgun sequenced six hunter-gatherer individuals from Houtaomuga site in Jilin, Northeast China, dated from 12000 to 2300 BP and, 3 farming individuals from Banlashan site in Liaoning, Northeast China, dated around 5300 BP. We find a high level of genetic continuity within northeast Asia Amur River Basin as far back to 12000 BP, a region where populations are speaking Tungusic languages. We also find our Compared with Houtaomuga hunter-gatherers, the Neolithic farming population harbors a larger proportion of ancestry from Houtaomuga related hunter-gathers as well as genetic ancestry from central or perhaps southern China. Our finding further suggests that the introduction of farming technology into Northeast Asia was probably introduced through demic diffusion.

A detail of the reported haplogroups of the Houtaomuga site:

houtaomuga-site-y-dna-mtdna

Y-DNA in Northeast Asia shows thus haplogroup N1b1 ~5000 BC, probably representative of the Baikal region, with a change to C2b-448del lineages before the Xiongnu period, which were later expanded by Mongols.

Common pitfalls in human genomics and bioinformatics: ADMIXTURE, PCA, and the ‘Yamnaya’ ancestral component

invasion-from-the-steppe-yamnaya

Good timing for the publication of two interesting papers, that a lot of people should read very carefully:

ADMIXTURE

Open access A tutorial on how not to over-interpret STRUCTURE and ADMIXTURE bar plots, by Daniel J. Lawson, Lucy van Dorp & Daniel Falush, Nature Communications (2018).

Interesting excerpts (emphasis mine):

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.

admixture-protocol
A protocol for interpreting admixture estimates, based on the assumption that the model underlying the inference is correct. If these assumptions are not validated, there is substantial danger of over-interpretation. The “Core protocol” describes the assumptions that are made by the admixture model itself (Protocol 1, 3, 4), and inference for estimating K (Protocol 2). The “Algorithm input” protocol describes choices that can further bias results, while the “Interpretation” protocol describes assumptions that can be made in interpreting the output that are not directly supported by model inference

Discussion

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.

admixture-pitfalls
Three scenarios that give indistinguishable ADMIXTURE results. a Simplified schematic of each simulation scenario. b Inferred ADMIXTURE plots at K= 11. c CHROMOPAINTER inferred painting palettes.

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.

PCA of SNP data

Open access Effective principal components analysis of SNP data, by Gauch, Qian, Piepho, Zhou, & Chen, bioRxiv (2018).

Interesting excerpts:

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 [3]. 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.

pca-how-to
DC-PCA biplot for oat data. The gradient in the CA-arranged matrix in Fig 13 is shown here for both lines and SNPs by the color scheme red, pink, black, light green, dark green.

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 [4]). 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.

Conclusion

Five simple recommendations for effective PCA analysis of SNP data emerge from this investigation.

  1. Use the SNP coding 1 for the rare or minor allele and 0 for the common or major allele.
  2. Use DC-PCA; for any other PCA variant, examine its augmented ANOVA table.
  3. 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.
  4. 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.
  5. 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.

pca-cwc-yamna-bbc
Principal Component Analysis (PCA) of the human Karsdorf and Sorsum samples together with previously published ancient populations projected on 27 modern day West Eurasian populations (not shown) based on a set of 1.23 million SNPs (Mathieson et al., 2015). https://doi.org/10.7554/eLife.36666.006

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.

So their lead archaeologist, Kristian Kristiansen, in The Indo-Europeanization of Europé (sic):

kristiansen-migrations
Kristiansen’s (2018) map of Indo-European migrations

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, dat British 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):

corded-ware-migrations
Nørtoft’s (2018) maps of Indo-European migrations.

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.

NOTE. You can read a more reasonable account of how haplogroup R1b-L51 and how R1-Z645 subclades expanded, and which dialects most likely expanded with them.

We don’t know where these scholars of the Danish workgroup stand at this moment, or if they ever had (or intended to have) a common position – beyond their persistent ideas of Yamnaya™ ancestral component = Indo-European and R1a must be Indo-European – , because each new publication changes some essential aspects without expressly stating so, and makes thus everything still messier.

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:

Related

Cystic fibrosis probably spread with expanding Bell Beakers

indo-european-uralic-bell-beaker-corded-ware-migrations

New paper (behind paywall) Estimating the age of p.(Phe508del) with family studies of geographically distinct European populations and the early spread of cystic fibrosis, by Farrell et al., European Journal of Human Genetics (2018).

Interesting excerpts (emphasis mine):

Our results revealed tMRCA average values ranging from 4725 to 1175 years ago and support the estimates of Serre et al. (3000–6000 years ago) [11], rather than Morral et al. (52,000 years ago) [6], but the latter figure was challenged by Kaplan et al. [26] because of disagreement with assumptions used in their calculations. In addition, the tMRCA values from western European regions reported herein refine the results of Fichou et al. [7] from a study of Breton CF patients in which the Estiage analysis suggested that the most common recent ancestor lived 115 generations ago. That tMRCA value, however, may have underestimated the age of p.(Phe508del) in Brittany due to consideration of all the haplotypes, even those that were reconstructed with ambiguities, as well as a potential bias associated with consanguinity due to including both haplotypes in homozygous families. In the more stringent Estiage analyses reported herein, those potential biases were avoided for all populations, leading to estimates of the oldest tMCRA values corresponding to the Early Bronze Age in western Europe, which is generally agreed to begin around 3000 BCE. This finding extends our results from a direct investigation of aDNA in teeth from Iron Age burials near Vienna around 350 BCE and allow us to conclude that p.(Phe508del) was present in that region long before then. More specifically, in the Austrian families studied, the Estiage data revealed a mean tMCRA value of 3575 years ago, which converts to 1558 BCE (Middle Bronze Age) [22].

Perhaps most remarkably, the estimated ages of p.(Phe508del) in the three western European regions (France, Ireland, and Denmark) were similar with closely overlapping 95% CI values. This observation is also in line with previously documented spatial autocorrelograms expressing genetic and geographical distance for these populations [24]. Such data provide more insight about the ancient origin of CF in our judgment—both when and where—and lead us to propose that CFTR p.(Phe508del) is derived from ancestors who lived in western Europe during the Bronze Age, as early as 2700 BCE, and that its relatively rapid dissemination occurred because of human migrations around the northwestern Atlantic trading routes [21] and then towards central and eastern Europe [22]. Diffusion from northwestern to central Europe in approximately 1000 years is consistent with the prominent Bronze Age migrations evident in the archeological record [21, 22] and from genomic studies of aDNA [27]. On the other hand, we are assuming a discrete origin of the principal CF-causing variant, but it is possible that p.(Phe508del) arose more than once or earlier, and then reached western Europe subsequently through Neolithic migrations.

cystic-fibrosis

[About Bell Beakers] (…) More specifically, their distinctive Bell Beaker pottery appeared and spread across western and central Europe beginning around 3000–2750 BCE and then disappeared between 2200 and 1800 BCE [22, 29]. Their migrations are linked to the advent of western and central European metallurgy, as they manufactured and traded metal goods, especially weapons, while traveling over long distances [30]. Most relevant to our study is the evidence that they migrated in a direction and over a time period that fits well with the pattern of tMRCA data we found for the p.(Phe508del) variant. Olalde et al. [29] have shown that both migration and cultural transmission played a major role in diffusion of the “Beaker Complex” and led to a “profound demographic transformation” of Britain after 2400 BCE. Moreover, the cultural elements that unite the widely distributed Beaker folk are so obvious that some have considered them a distinct ethnicity of Bronze Age people [33].

From our results, we propose the novel concept that large scale, long term west-to-east migrations of the Bell Beaker Europeans [22, 28–30] during the Bronze Age, could explain the dissemination of p.(Phe508del) in Europe and its documented northwest-to-southeast gradient [4].In fact, our tMRCA data show a temporal gradient also.

As you can see from the references, they consulted with Barry Cunliffe (or people accepting his theory), who is obsessed with Bell Beakers expanding Celtic languages from the British Isles. He is like the British equivalent of Danish scholar Kristian Kristiansen, and his obsession with Corded Ware = Indo-European (and Germanic = CWC Denmark), immutable no matter what genetic results might show.

The funny thing is, the interpretation of the paper is probably right. From what we can see in the data, it is quite possible that the disease spread with expanding Bell Beakers…only it spread from the East group in Hungary, i.e. from east to west. The regional difference in TMRCA and apparent west—east cline would point to the different expansions of affected lineages in the corresponding regions, and not to an origin in the British Isles.

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The importance of fine-scale studies for integrating palaeogenomics and archaeology

eurasian-genomes-published

Short review (behind paywall) The importance of fine-scale studies for integrating paleogenomics and archaeology, by Krishna R. Veeramah, Current Opinion in Genetics & Development (2018) 53:83-89.

Abstract (emphasis mine):

There has been an undercurrent of intellectual tension between geneticists studying human population history and archaeologists for almost 40 years. The rapid development of paleogenomics, with geneticists working on the very material discovered by archaeologists, appears to have recently heightened this tension. The relationship between these two fields thus far has largely been of a multidisciplinary nature, with archaeologists providing the raw materials for sequencing, as well as a scaffold of hypotheses based on interpretation of archaeological cultures from which the geneticists can ground their inferences from the genomic data. Much of this work has taken place in the context of western Eurasia, which is acting as testing ground for the interaction between the disciplines. Perhaps the major finding has not been any particular historical episode, but rather the apparent pervasiveness of migration events, some apparently of substantial scale, over the past ∼5000 years, challenging the prevailing view of archaeology that largely dismissed migration as a driving force of cultural change in the 1960s. However, while the genetic evidence for ‘migration’ is generally statistically sound, the description of these events as structured behaviours is lacking, which, coupled with often over simplistic archaeological definitions, prevents the use of this information by archaeologists for studying the social processes they are interested in. In order to integrate paleogenomics and archaeology in a truly interdisciplinary manner, it will be necessary to focus less on grand narratives over space and time, and instead integrate genomic data with other form of archaeological information at the level of individual communities to understand the internal social dynamics, which can then be connected amongst communities to model migration at a regional level. A smattering of recent studies have begun to follow this approach, resulting in inferences that are not only helping ask questions that are currently relevant to archaeologists, but also potentially opening up new avenues of research.

Interesting excerpts (emphasis mine, reference numbers removed for clarity):

There are two major, somewhat intertwined, problems that currently exist.

First, archaeologists are not critiquing whether the migrations identified by paleogenomics using sophisticated population genetic machinery are actually occurring. Instead, the technical criticism arrives in terms of how these migrations are being ascribed to specific cultures. In many paleogenomic papers, there is a tendency (and often an analytical and technical need) to associate samples with particular archaeological cultures, for which all samples are then treated as possessing some kind homogenous and pervasive social identity that is bound in space and time. The major critiques of this thus far have been directed to those studies examining Corded-Ware and Bell-Beaker-related individuals and their potential relationship to the Yamnaya [Vander Linden (2016), Heyd (2017), Furholt (2017)], but are applicable to many other ‘migration’ scenarios described in the recent literature. This is compounded by the use of sometimes small numbers of samples to represent certain cultures from a particular geographic area as representatives of the entire culture at a supra-regional level. Yet often these archaeological cultures such as Corded-Ware and Bell-Beaker themselves show considerable variability in space and time, and even within cemeteries, which is not factored into the genetic analysis.

From a population geneticists point of view, this kind of simplification is somewhat understandable and will often likely have very little impact on the final analysis, given that the primary goal is usually to use ancient samples to better understand modern genetic variation. Though there may be a specific historical interest in some of these past events, I would argue that the aim for most population geneticists at a higher level is to try and fit modern patterns of genetic variation using the simplest models possible that take into account past demographic events (for example fitting f-statistics using the ADMIXTUREGRAPH approach), as this is how we are trained. Although sharing an archaeological culture may not mean that a set of individuals are part of the same homogeneous social group in reality, this approach may be a good enough heuristic to find broad genetic connections compared to another group represented by a different culture, which can then ultimately help understand and model modern human population structure. However, for an archaeologists interested in the ancient individuals themselves and their social identity, this lumping is unsatisfactory, where sophisticated narratives of the individual migrants and their ancient communities are the intended goal.

eurasian-genomes
From the paper. Barplot showing cumulative number of ancient Eurasian genomes published on a yearly basis up to 8th July 2018. Includes samples undergoing both whole genome shotgun and SNP capture sequencing.

The second related problem is that ‘migration’ in the sense used currently in the paleogenomics literature lacks sufficient detail to be of much use for an archaeologists attempting to disentangle the complex social dynamics within and between communities. To truly understand the role of migration as a social process and its contribution towards cultural changes, it is necessary to describe it as a structured behaviour, rather than treating it as an explanatory ‘black box’. Are the migrations occurring as a result of short range waves-of-advance movements, or as long-distance movements via leapfrogging models or stream migrations along established routes dependent on key kinship networks. Are there return migrants, and are some subset of individuals more predisposed to migration driving the signals? Although such models were implemented in past studies (even with classical markers [1]) and are part of the population genetics literature, they are lacking in the current paleogenomics literature when discussing migration. The finding that there is an increase of 12.3% of ancestry type X in population A compared to the preceding population B that is suggestive of a migration, is not particularly useful for examining these kind of models. It is also unclear to what degree standard population genetic parameters estimated from genomic data such as effective population size, Ne, and gene flow are relevant to models studied in archaeology, given they reflect (somewhat undefined) long-term population sizes and average rates of movements over time, rather than reflecting any kind of reality of census size and mobility in the ancient communities the archaeologists are actually attempting to study.

The text goes on to talk about ways of studying fine-grained social dynamics of local cultures, such as:

define levels of genetic relatedness, but also in terms of material culture, age, sex, stress and activity indicators, stable isotopes for diet reconstruction (nitrogen, d13C and d15N, carbon, 13C/12C) and strontium and oxygen isotopes for mobility (87Sr/86Sr, d18O). Where possible, sites should be examined over multiple generations. In addition it will be incredibly useful to characterize the impact of disease in these communities, which is also proving to be a highly fruitful realm for paleogenomics.

I would say that the main problem is not the obvious limitations of palaeogenomics in terms of identifying prehistoric ethnolinguistic communities and their evolution, which is why it is just another tool to complement archaeology and linguistics. The main problem is the narrow understanding that some people have of the inherent limitations of palaeogenomics – especially when it interests them – , when publicizing simplistic conclusions based on these tools and their results. And I am not referring only to amateurs.

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Origin of horse domestication likely on the North Caspian steppes

Open access Late Quaternary horses in Eurasia in the face of climate and vegetation change, by Leonardi et al. Science Advances (2008) 4(7):eaar5589.

Interesting excerpts (emphasis mine):

Here, we compiled an extensive continental-scale database, consisting of 3070 radiocarbon dates associated to horse paleontological and archeological finds across the whole of Eurasia, that has been analyzed in association with coarse-scale paleoclimatic reconstructions. We further collected the number of identified specimens (NISP) frequency data for horses versus other ungulates in 1120 archeological layers in Europe (…) This ma.ssive amount of data allowed us to track,with unprecedented details, how the geographic distribution of the species changed through time

Geographic range through time

For most analyses, the data have been divided into climatic periods: pre-LGM(older than 27 ka B.P.), LGM(27 to 18 ka B.P.), Late Glacial (18 to 11.7 ka B.P.), Preboreal (11.7 to 10.6 ka B.P.), Boreal (10.6 to 9.1 ka B.P.), Early Atlantic (9.1 to 7.5 ka B.P.), Late Atlantic (7.5 to 5.5 ka B.P.), and Recent (younger than 5.5 ka B.P.) (Fig. 1, A and B). The spatial and temporal distribution of horse remains compiled in our database reveals a strong imbalance in Eurasia (Fig. 1, A and B).

We found a common trend in both regions for a high number of occurrences at the end of the Pleistocene (with a decrease during the LGM, only visible in Europe), followed by a drastic reduction in the Early and Middle Holocene, and a relative increase toward more recent times. These included both the Early Atlantic in Europe, which started ~9.1 ka B.P., and the time range after 5.5 ka B.P. for Asia. The horse fossil record appears ubiquitous throughout Europe in the Late Pleistocene, while in the Early and Middle Holocene the finds are concentrated in central-western Europe and Iberia. From 7.5 ka B.P., the number of finds increases markedly, and the geographical distribution extends toward the east and southeast.

horse-distribution-climate
Horse occurrences through time. (A) Horse occurrences through time. Histograms showing the number of horse observations in Europe (left panel) and Asia (right panel) for each time bin (top) and for climatic period (bottom). Only time bins with more than 10 observations (black horizontal line) have been considered for the SDM analyses. From 22 ka B.P. backward (gray vertical line), time bins cover 2 ka following the available paleoclimatic reconstructions. The central map shows the boundaries considered while defining European and Asian regions, with the black line representing the Urals. The zoomed area shows the geographical resolution of the climatic reconstructions, with each pixel representing a grid cell. (B) Geographic distribution of horse occurrences. Maps showing horse occurrences for each climatic period in Europe (left) and Asia (right).

Different Asian and European niches

This analysis revealed that, in both continents, horses occupied only a portion of the climatic space available. The range covered by random locations shows that the paleoecological conditions present in Europe were only a subset of those found in Asia. However, European horses occupied a much wider climatic space than in Asia, with only limited overlap between the two ranges.

Horses conquered temperate environments from a European source

There is no evidence of climatic barriers between those two populations through time because the forecasts from Europe and Asia always overlap in central Eurasia, except 5 ka B.P. (figs. S3 and S4). An alternative explanation is the role of the Urals as a potential constraint for the dispersal of horses between Europe and north central Asia.

climatic-suitability-horses
Climatic suitability. (A) Cumulative climatic suitability for the past 44 ka based on simulation on the European (left), Eurasian (middle), and Asian (right) data sets. To correct for sampling bias in the Eurasian data set, for each time slice, all estimates and projections for Eurasia are performed considering 100 random resampling of European occurrences in the same number as Asian occurrences. The darker the colors, themore stable the climatic suitability for horses (climatic niche = p-Hor) through time. (B) Projection of climatic suitability across Eurasia in different climatic periods based on occurrences in Europe (left), Eurasia (middle), and Asia (right). Because of the scarcity of data available for Asia, no models for the Holocene have been possible for both Asia and Eurasia, with the exception of 5 and 3 ka B.P. (both included in the “Recent” period).

Climatic and habitat association patterns for horses in Europe support increasing habitat fragmentation

The decrease of horse remains in Europe is not characterized by a geographic reduction in the overall extent of the area occupied by the species but in a drop of frequencies in a geographic extent that does not vary much between the Late Glacial and the Early Atlantic (Figs. 1B and 4B). This pattern is more likely to result from habitat fragmentation than from a geographic shift in the climatic range suitable for the species, as observed for many animals during the LGM (23).

In the whole period ranging from the Preboreal (11.7 to 10.6 ka B.P.) to the Late Atlantic (7.5 to 5.5 ka B.P.), the total amount of land space most and likely suitable to horses is wider than in the Late Glacial, and only between 8 to 7 ka ago the European range appears patchy and fragmented (Fig. 4C). When comparing each of four successive time bins during the Holocene (8, 7, 6, and 5 ka B.P., respectively) (Fig. 4E), the difference in successive p-Hor values in Europe shows that the suitability for the species in Iberia, northeastern France, Italy, the Balkans, and eastern Europe steadily increased, while in Central Europe strong differences can be observed between neighboring regions.

horse-europe-asia
Analyses of the European data set and biomefrequency. (A) Distribution through time of the frequency of horse remains in Europe calculated as NISP of horses versus other ungulates. (B) Density of horse remains through time in Europe, calculated as NISP of horses versus other ungulates. The numbers at the bottom of each bar represent the number of observations falling in each class, from 0 to >5%. (C) Climatic suitability for horses in Europe between 10 and 3 ka B.P. (D) Climatic suitability per time period. Percentage of land cells in Europe with a value of suitability for horses (p-Hor) > 0.5 and p-Hor > 0.8. (E) Holocene climatic amelioration. Difference in p-Hor in Europe comparing five successive time bins during the Holocene: 9, 8, 7, 6, and 5 ka B.P. Eachmap shows the difference in themore recent distribution compared to the previous one. (F) Environmental reconstructions in themacro area surrounding horse finds in Europe (left) and Asia (right) per climatic period. The lighter the color, the less forested is the region. The numbers at the bottom of the bars show the number of occurrences in closed environments over all the observations. The dotted line represents a frequency of 0.5.

Taken at face value, this pattern would suggest that horses were not restricted to open environments but could equally well inhabit closed, forested environments, as previously suggested (18). However, as others recently emphasized (19), the faunal associations inHolocene sites from Europe suggest a different pattern. The PCAs based on faunal assemblages (figs. S1 and S2) separate on the second principal component sites characterized by ungulates associated to forested areas (red deer, wild boar, and roe deer) and all other animals, associated to semi-open and open environments, including horses for most records.

Together, the contrast between the reconstructed microscale and macroscale vegetable coverage in Europe, the increase of horses in mainly forested macroregions, and the spatial pattern of extinction suggest that, from the beginning of the Holocene, the suitable environment became more and more patchy, with open areas increasingly fragmented by forests, where wild populations of horses could have survived in isolation until one or several waves of arrivals of domestic horses, leading to either local admixture or a full replacement of the preexisting local populations.

Conclusion

Our data show that, up to 5.5 ka ago, horse finds do not show association with species characteristic of forested areas such as wild boar and roe deer. We infer that the open and semi-open habitats occupied by horses on a narrow geographic scale appear less and less frequent at a macroenvironmental scale, supporting the possibility of increasing fragmentation of open habitats. This event is also likely to have led to an intensification of genetic isolation for the remaining horse populations, a pattern that still needs to be tested on genomic data.

The suitability of both Iberia and eastern Europe appears constant throughout the entire post-LGM period, in line with these regions being hotspots of genetic diversity and, possibly, the refugia sources for the recolonization of the continent (11). While the Pontic-Caspian region appears not suitable for European horses around the time when horses where first domesticated some 5.5 ka ago (6), part of this region appears suitable for the Asian horses (with the Caspian Sea as the westernmost boundary). This may suggest that horse domestication started from a population background related to an Asian ancestry and that the further spread of the domesticated horses in Europe involved either adaptation to novel niches (possibly through selective breeding) or the application of domestication techniques to local horse populations pre-adapted to these environmental conditions. Testing this scenario will require mapping the genetic structure of the Eurasian horse population within the fifth to third millennium BCE.

Some remarks

Cultural-anthropological research and archaeological remains (see here), genetics (see here and here), and now also thorough palaeoclimatic and archaeological models point to the North Caspian region, settled by the Khvalynsk culture, as the most likely earliest origin of horse domestication. The paper also supports the favorable conditions of western Europe up to Iberia for the introduction of a horse-riding culture.

I intended to write a post about the myth of Corded Ware horse riders, but for the moment I haven’t found the time. Not that Corded Ware pastoralists didn’t have horses, or could not ride them: they were a highly mobile culture of pastoralists stemming from eastern Poland / western Ukraine, so they must have known horses, like many other European cultures of the late 4th / early 3rd millennium influenced by expanding Yamna settlers. But it just cannot be said to have formed an essential part of their culture, as it was for Khvalynsk-Novodanilovka, and especially Yamna and later East Bell Beaker, Sintashta, etc.

A mere look at these maps suffices to assess the limited role of the horse in north-eastern Europe, the only region where groups of late Corded Ware-derived cultures survived the expansion of Yamna, and especially East Bell Beakers after ca. 2500 BC, which transformed Western, Northern, and Central Europe, and even East Europe reaching the modern Baltic countries, Belarus, and Romania. Even Trzciniec was born out of the influence from expanding Bell Beakers into earlier Corded Ware territory, although the later (Iron Age) relevance of this culture was probably quite limited.

As you can imagine, without horses and horse symbolism, horse riding, carts, and intensive cattle-breeding (associated with Yamna and the broad, east-central European grasslands typical of steppe regions), there can be no Proto-Indo-European, whose reconstructed vocabulary is particulary rich in horse-related words, and whose reconstructed culture, society, and religion cannot be understood without the domesticated horse. In forest regions to the north-east and eastern Europe, there was apparently little space for horses, but plenty of room for other ungulates and thus hunting, and indeed Uralic languages

In the upcoming months we will see R1a-fans associating Proto-Indo-Europeans more and more with wool, and sheep, and corded ware, and forest regions, until the proposed homeland shifts to the Baltic and Finland, instead of dat boring horse-riding people of the steppes…No wait, it’s already happening.

NOTE. Also open access is the recent Horse Y chromosome assembly displays unique evolutionary features and putative stallion fertility genes, by Janečka et al. Nature Communications (2018).

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When Bell Beakers mixed with Eneolithic Europeans: Pömmelte and the Europe-wide concept of sanctuary

pommelte-enclosure

Recent open access paper The ring sanctuary of Pömmelte, Germany: a monumental, multi-layered metaphor of the late third millennium BC, by Spatzier and Bertemes, Antiquity (2018) 92(363):655-673.

Interesting excerpts (emphasis mine):

In recent decades, evidence has accumulated for comparable enclosures of later dates, including the Early Bronze Age Únětice Culture between 2200 and 1600 BC, and thus into the chronological and cultural context of the Nebra sky disc. Based on the analysis of one of these enclosure sites, recently excavated at Pömmelte on the flood plain of the Elbe River near Magdeburg, Saxony-Anhalt, and dating to the late third millennium BC

The main occupation began at 2321–2211 cal BC, with the stratigraphically earliest features containing exclusively Bell Beaker finds. Bell Beaker ceramics continue after 2204–2154 cal BC (boundary occupation I/II), although they were probably undecorated, but are now complemented by Únětice Culture (and other Early Bronze Age) types. At this time, with features common to both cultures predominate. Only contexts dating to the late main occupation phase (late phase II) and thereafter contained exclusively Únětice Culture finds. Evidently, the bearers of the Bell Beaker Culture were the original builders of the enclosure. During a second phase of use, Final Neolithic and Early Bronze Age cultures coexisted and intermingled. The material remains, however, should not be taken as evidence for successive groups of differing archaeological cultures, but as witnesses to a cultural transition from the Bell Beaker Culture to the Únětice Culture (Spatzier 2015). The main occupation ended 2086–2021 cal BC with the deconstruction of the enclosure; Bell Beaker finds are now absent. Finally, a few features (among them one shaft) and radiocarbon dates attest the sporadic re-use of the site in a phase of abandonment/re-use that ended 1636– 1488 cal BC.

pommelte-enclosure-occupation-stratigraphy
Cultural sequence and chronological model of the Pömmelte enclosure’s occupation (dates in 1σ-precision) (designed by André Spatzier).

How the above-ground structures possibly influenced perception may reveal another layer of meaning that highlights social functions related to ritual. While zone I was disconnected from the surroundings by a ‘semi-translucent’ post-built border, zones II/III were separated from the outside world by a wooden wall (i.e. the palisade), and zone III probably separated individuals from the crowd gathered in zone II. Accessing the interior or centre therefore meant passing through transitional zones, to first be secluded and then segregated. Exiting the structure meant re-integration and re-connection. The experience possibly induced when entering and leaving the monument reflects the three stages of ‘rites of passage’ described by van Gennep (1909): separation, liminality and incorporation. The enclosure’s outer zone(s) represents the pre- and post-liminal phase; the central area, the liminal phase. Seclusion and liminality in the interior promoted a sense of togetherness, which can be linked to Turner’s “communitas” (1969: 132–33). We might therefore see monuments such as the Pömmelte enclosure as important communal structures for social regulation and the formation of identity.

ring-sanctuary-of-pommelte
Layers of meaning of the Pömmelte enclosure as deduced from the archaeological record (design by André Spatzier).

(…) The long-term stability of these connotations must be emphasised. As with the tradition of making depositions, these meanings were valid from the start of the occupation — c. 2300 BC — until at least the early period following the deconstruction event, c. 2050 BC. While the spatial organisation and the solar alignment of the main entrances were maintained throughout the main occupation, stone axes and ‘formal’ graves indicate the continuation of the spatial concepts described above until the twentieth to nineteenth centuries BC.

These layers of meaning mirror parallel concepts of space including, although not necessarily restricted to, the formation of group identities (see Hansen & Meyer 2013: 5). They can perhaps be better understood as a ‘cosmological geography’ manifested in the symbolism of superimposed levels of conceptual ideas related to space and to certain cardinal points (Figure 8). This idea is closely related to Eliade’s (1959: 29–36) understanding of “organized — hence comicized — territory”, that is territory consecrated to provide orientation within the homogeneity of the chaotic ‘outside world’, and the equivalence of spatial consecration and cosmogony. Put differently, the Pömmelte enclosure can be interpreted as a man-made metaphor and an icon of the cosmos, reflecting the Weltanschauung (a comprehensive conception of the world) of the people who built and used it. By bringing together Eliade and Rappaport’s ideas of meaningfulness in relation to religious experience (Rappaport 1999: 391–95), it may be argued that Pömmelte was a place intended to induce oneness with the cosmos. In combining multiple layers that symbolically represent different aspects of life (first-ordermeaning), the enclosure became an icon metaphorically representing the world (second-order-meaning). As this icon was the place to reaffirm life symbolism ritually, through their actions, people perhaps experienced a sense of rootedness in, or unity with, the cosmos (highest-order-meaning). Although we can only speculate about the perceptions of ancient people, such a theory aiming to describe general principles of religious experience can provide insight.

Conclusions

The circular enclosure of Pömmelte is the first Central European monumental complex of primarily sacred importance that has been excavated and studied in detail. It reveals aspects of society and belief during the transition from the Final Neolithic to the Early Bronze Age, in the second half of the third millennium BC. Furthermore, it offers details of ritual behaviour and the way that people organised their landscape. A sacred interior was separated from the profane environment, and served as a venue for rites that secured the continuity of the social, spiritual and cosmic order. Ancestor worship formed another integral part of this: a mound-covered burial hut and a square-shaped ditch sanctuary (located, respectively, within and near the enclosure’s south-eastern sector; cf. Figure 2)—dating to 2880–2580 cal BC and attributed to the Corded Ware Culture (Spatzier 2017a: 235–44)—suggest that this site was deliberately chosen. With construction of the ring sanctuary, this place gained an immense expansion in meaning—comparable to Stonehenge. Through architectural transformation, both of these sites developed into sanctuaries with increasingly complex religious functions, including in relation to the cult of the dead. The cosmological and social functions, and the powerful symbolism of the Nebra sky disc and hoard (Meller 2010: 59–70), are reflected in Pömmelte’s monumental architecture.

All of these features—along with Pömmelte’s dating, function and complex ring structure—are well documented for British henge monuments (Harding 2003; Gibson 2005). The continuous use of circular enclosures in Central Europe from around 3000– 1500 BC remains to be confirmed, but strong evidence indicates usage spanning from the fifth to the first millennia BC (Spatzier 2017a: 273–96). From 2500 BC onwards, examples in Central Europe, Iberia and Bulgaria (Bertemes 2002; Escudero Carrillo et al. 2017) suggest a Europe-wide concept of sanctuary. This indicates that in extensive communication networks at the beginning of bronze metallurgy (Bertemes 2016), intellectual and religious contents circulated alongside raw materials. The henge monuments of the British Isles are generally considered to represent a uniquely British phenomenon, unrelated to Continental Europe; this position should now be reconsidered. The uniqueness of Stonehenge lies, strictly speaking, with its monumental megalithic architecture.

pommelte-enclosure-space
Model of the spatial organisation of the Pömmelte enclosure (designed by André Spatzier).

The Classical Bell Beaker heritage

No serious scholar can argue at this point against the male-biased East Bell Beaker migrations that expanded the European languages related to Late Proto-Indo-European-speaking Yamna (see David Reich’s comments), and thus most likely North-West Indo-European – the ancestor of Italo-Celtic, Germanic, and Balto-Slavic, apart from Pre-Celtic IE in the British Isles, Lusitano-Galician in Iberia, or Messapic in Italy (see here a full account).

With language, these migrants (several ten thousands) brought their particular Weltanschauung to all of Western, Central, and Northern Europe. Their admixture precisely in Hungary shows that they had close interactions with non-Indo-European peoples (genetically related to the Globular Amphorae culture), something that we knew from the dozens of non-Indo-European words reconstructed exclusively for North-West Indo-European, apart from the few reconstructed non-Indo-European words that NWIE shares with Palaeo-Balkan languages, which point to earlier loans from their ancestors, Yamna settlers migrating along the lower Danube.

It is not difficult to imagine that the initial East Bell Beaker group shared a newly developed common cosmological point of view that clashed with other neighbouring Yamna-related worldviews (e.g. in Balkan EBA cultures) after the cultural ties with Yamna were broken. Interesting in this respect is for example their developed (in mythology as in the new North-West Indo-European concept) *Perkwūnos, the weather god – probably remade (in language as in concept) from a Yamna minor god also behind Old Indian parjányas, the rain god – as one of the main gods from the new Pantheon, distinct from *Dyēus patēr, the almighty father sky god. In support of this, the word *meldh-n- ‘lightning’, behind the name of the mythological hammer of the weather god (cf. Old Norse Mjǫllnir or Latvian Milna), was also a newly coined North-West Indo-European term, although the myth of the hero slaying the dragon with the magical object is older.

perkunos-perkunas
The Hand of Perkūnas by Mikalojus Konstantinas Čiurlionis, from Wikipedia

Circular enclosures are known in Europe since the Neolithic. Also, the site selected for the Pömmelte enclosure had been used to bury Corded Ware individuals some centuries before its construction, and Corded Ware symbolism (stone axe vs. quern) is seen in the use given by Bell Beakers and later Únětice at this place. All this and other regional similarities between Bell Beakers and different local cultures (see here an example of Iberian Bell Beakers) points to syncretism of the different Bell Beaker groups with preceding cultures in the occupied regions. After all, their genealogical ancestors included also those of their maternal side, and not all encountered males disappeared, as is clearly seen in the resurge of previous paternal lineages in Central-East Europe and in Scandinavia. The admixture of Bell Beakers with previous groups (especially those of similar steppe-related ancestry from Corded Ware) needs more complex analyses to clarify potential early dialectal expansions (read what Iosif Lazaridis has to say).

The popular “big and early” expansions

These syncretic trends gave rise to distinct regional cultures, and eventually different local groups rose to power in the new cultural regions and ousted the old structures. Social norms, hierarchy, and pantheons were remade. Events like this must have been repeated again and again in Bronze and Iron Age Europe, and in many cases it was marked by a difference in the prevailing archaeological culture attested, and probably accompanied by certain population replacements that will be seen with more samples and studies of fine-scale population structure.

Some of these cultural changes, marked by evident haplogroup or admixture replacement, are defined as a ‘resurge’ of ancestry linked to previous populations, although that is obviously not equivalent to a resurge of a previous cultural group, because they usually represent just a successful local group of the same supraregional culture with a distinct admixture and/or haplogroup (see e.g. resurge of R1a-Z645 in Central-East European Bronze Age). Social, religious, or ethnic concepts may have changed in each of these episodes, along with the new prestige dialect.

NOTE. A recent open access paper on two newly studied Middle Bronze Age inhumations from Stonehenge give an interesting idea of potential differences in social identities, in ancestry and geographic origin (which characterize ethnicity) may have been marked by differences in burial ceremonies: Lives before and after Stonehenge: An osteobiographical study of four prehistoric burials recently excavated from the Stonehenge World Heritage Site, by Mays et al. Journal of Archaeological Science: Reports (2018) 20:692-710.

This must have happened then many times during the hundreds (or thousands in some cases) of years until the first attestation of a precise ancient language and culture (read e.g. about one of the latest branches to be attested, Balto-Slavic). Ancient language contacts, like substrates or toponymy, can only rarely be detected after so many changes, so their absence (or the lack of proper studies on them) is usually not relevant – and certainly not an argument – in scholarly discussions. Their presence, on the other hand, is a proof of such contacts.

chalcolithic_late_Europe_Bell_Beaker
Diachronic map of Late Copper Age migrations including Classical Bell Beaker (east group) expansion from central Europe ca. 2600-2250 BC

We have dozens of papers supporting Uralic dialectal substrate influence on Pre-Germanic, Proto-Balto-Slavic, and Pre- and Proto-Indo-Iranian (and even Proto-Celtic), as well as superstrate influence of Palaeo-Germanic (i.e. from Pre- to Proto-Germanic) and Proto-Balto-Slavic into Proto-Finno-Saamic, much stronger than the Indo-Iranian adstrate influence on Finno-Ugric (see the relative importance of each influence) which locates all these languages and their evolution to the north and west of the steppe (with Proto-Permic already separated, in North-East Europe, as is Proto-Ugric further east near the Urals), probably around the Baltic and Scandinavia after the expansion of Bell Beakers. These connections have been known in linguistics for decades.

Apart from some early 20th century scholars, only a minority of Indo-Europeanists support nowadays an Indo-European (i.e. centum) substrate for Balto-Slavic, to keep alive an Indo-Slavonic group based on a hypothetical 19th century Satem group; so e.g. Holzer with his Temematic, and Kortlandt supporting him, also with some supposed Indo-European substrate with heavy non-Indo-European influence for Germanic and Balto-Slavic, that now (thanks mainly to the views of the Copenhagen group) have been linked to the Corded Ware culture, as it has become clear even to them that Bell Beakers expanded North-West Indo-European.

NOTE. The Temematic etymologies have been (all of them) fully dismissed e.g. in Matasović (2013). I have already explained why an Indo-Slavonic group from Sredni Stog is not tenable, and genetics (showing Late PIE only from Yamna expansions) is proving that, too.

For their part, only a minority among Uralicists, such as Kuz’mina, Parpola or Häkkinen, believe in an ‘eastern’ origin of Uralic languages, around the Southern Urals. Genomic finds – like their peers – are clearly not supporting their views. But even if we accept this hypothesis, there is little space beyond Abashevo and related East Corded Ware cultures after the recent papers on Corded Ware and Fennoscandian samples. And yet here we are:

The Copenhagen “Homeland” interactive map

copenhagen-group-map
Brought to you by the Copenhagen fantasy map series, Indo-Europeans after (no, really, after) the expansion of Yamna settlers in Hungary ca. 2700 BC: Yamna settlers have magically disappeared. Yamna-related Balkan EBA cultures and the hundreds of Yamna kurgans around the Lower Danube and in Hungary up to Saxony-Anhalt do not exist. Dat huge mythical Middle Dnieper territory lasting (unchanged) for a thousand years, in sooo close contact with Yamna territory (so beautifully ‘linked’ together that they must have been BFFs and admixed!). Uralic Mesolithic hunter-gatherers resisting IE invasions in Volosovo for 1,500 years like Asterix’ Gaulish village against the Romans. Tiny pockets of Bell Beakers will eventually emerge from (surprise!) Corded Ware territories beautifully scattered over Central and Northern Europe (unlike those eastern CWC mega-regions). And, of course, you can almost see Kroonen & Iversen’s Kurgan Pre-Germanic mixing already with their agricultural substrate TRB precisely in full-IE Denmark (quite appropriate for the Danish school). And sheep symbols representing wool finds, for no reason. A great map to mock for years to come, with each new genetic paper.

The new propaganda tool GIS timeline map of the Copenhagen group:

  • consciously ignores Yamna settlers along the Danube, in the Balkans, and in Hungary, and initial East Bell Beakers, i.e. the obvious origin and expansion of North-West Indo-Europeans, but in contrast magnifies (and expands in time) regions for Sredni Stog / Corded Ware cultures (which suggests that this is yet another absurd attempt to revive the theories of the Danish school…);
  • substitutes arrows for Kron-like colors (where danger red = Indo-European) with the same end result of many other late 20th century whole-Europe Kurgan maps, linking Sredni Stog and Corded Ware with Yamna, but obviating the precise origin of Corded Ware peoples (is it Sredni Stog, or is it that immutable Middle Dnieper group? is it West Yamna, or Yamna Hungary? is it wool, or is it wheels?);
  • relegates Uralic speakers to a tiny corner, a ‘Volosovo’ cultural region, thus near Khvalynsk/Yamna (but not too much), that miraculously survives surrounded by all-early-splitting, all-Northern Eneolithic Indo-Europeans, thus considering Uralic languages irrelevant not only to locate the PIE Urheimat, but also to locate their own homeland; also, cultures identified in color with Uralic speakers expand until the Iron Age with enough care not to even touch in the map one of the known R1a samples published to date (because, for some people, apparently R1a must be Indo-European); and of course N1c or Siberian ancestry are irrelevant, too;
  • and adds findings of wheels and wool probably in support of some new ideas based on yet another correlation = causation argument (that I cannot then properly criticize without access to its reasoning beyond cute SmartArt-like symbols) similar to their model – already becoming a classic example of wrong use of statistical methods – based on the infamously named Yamnaya ancestral component, which is obviously still used here, too.

The end result is thus similar to any other simplistic 1990s Gimbutas (or rather the recently radicalized IE Sredni Stog -> Corded Ware -> BBC version by the Danish workgroup) + 2000s R1a-map + 2010s Yamnaya ancestry; but, hard to believe, it is published in mid-2018. A lot of hours of senseless effort, because after its publication it becomes ipso facto outdated.

For comparison of Yamna and Bell Beaker expansions, here is a recent simplistic, static (and yet more accurate) pair of maps, from the Reich Lab:

corded-ware-bell-beaker
Cultural maps from Eneolithic and Chalcolithic cultures in Wang et al. (2018).

If the Copenhagen group keeps on pushing Gimbutas’ long ago outdated IE Sredni Stog -> Corded Ware theory as modified by Kristiansen, with their recently invented Corded Ware -> Bell Beaker model in genetics, at some point they are bound to clash with the Reich-Jena team, which seems to have less attachment to the classic Kurgan model and the wrong interpretations of the 2015 papers, and that would be something to behold. Because, as Cersei would say: “When you play the game of thrones, you win or you die. There is no middle ground.” And when you play the game of credibility, after so many, so wrong publications, well…

NOTE. I have been working on a similar GIS tool for quite some time, using my own maps and compiled genetic data, which I currently only use for my 2018 revision of the Indo-European demic diffusion model. Maybe within some weeks or months I will be able to publish the maps properly, after the revised papers. It’s a pitty that so much work on GIS and analysis with genetic data and cultural regions has to be duplicated, but I intend to keep some decent neutrality in my revised cultural maps, and this seems impossible at this point with some workgroups who have put all their eggs in one broken basket…

Related

Pre-Germanic born out of a Proto-Finnic substrate in Scandinavia

indo-european-yamnaya-corded-ware

A commenter, Old Europe, drew my attention to the Uralic (Finnic-Saamic) substrate in Germanic proposed by Schrijver in Chapter V. Origins of Language Contact and the Origins of the Germanic Languages, Routledge (2014).

I wanted to share here some interesting excerpts (emphasis mine):

NOTE. I have avoided many detailed linguistic discussions. You should read the whole chapter to check them out.

The origins of the Germanic subfamily of Indo-European cannot be understood without acknowledging its interactions with a language group that has been its long-time neighbour: the Finnic subgroup of the Uralic language family. Indo-European and Uralic are linked to one another in two ways: they are probably related to one another in deep time — how deep is impossible to say3 — and Indo-European has been a constant source from which words were borrowed into Uralic languages, from the fourth millennium BC up to the present day.4 The section of the Uralic family that has always remained in close proximity to the Indo-European dialects which eventually turned into Germanic is Finnic. I use the term Finnic with a slightly idiosyncratic meaning : it covers the Finno-Saamic protolanguage and both of its children, Saami and Balto-Finnic.(…)

finnic-family-tree-schrijver
Schrijver (2014). The Finnic family tree (simplified)

Linguistically, the relationship between Indo-European and Uralic has always been asymmetrical. While hundreds of loanwords flowed into Uralic languages from Indo-European languages such as Germanic, Balto-Slavic, Iranian, and Proto-Indo-European itself, hardly any Uralic loanwords have entered the Indo-European languages (apart from a few relatively late dialectal loans into e.g. Russian and the Scandinavian languages). This strongly suggests that Uralic speakers have always been more receptive to ideas coming from Indo-European–speaking areas than the other way around. This inequality probably began when farming and the entire way of life that accompanies it reached Uralic-speaking territory via Indo-European–speaking territory, so that Uralic speakers, who traditionally were hunter-gatherers of the mixed and evergreen forest zone of northeastern Europe and gradually switched to an existence as sedentary farmers, were more likely to pick up ideas and the words that go with them from Indo-European than from anywhere else.

Farming requires a different mind-set from a hunter-gatherer existence. Farmers are generally sedentary, model the landscape, and have an agricultural calendar to determine their actions. Hunter-gatherers of the northern forest zone are generally nomadic, and rather than themselves modelling the natural environment they are modelled by it: their calendar depends on when and where a particular natural resource is available.(…)

All of this is no doubt a simplification of the thousands of years of associations between speakers of Uralic and speakers of Indo-European, but the loanword evidence strongly suggests that by and large relations between the two groups were highly unequal. The single direction in which loanwords flowed, and the mass of loanwords involved, can be compared with the relation between Latin and the vernacular languages in the Roman Empire, almost all of which disappeared in favour of Latin. It is therefore certain that groups of Uralic speakers switched to Indo-European. The question is whether we can trace those groups and, more particularly, whether Finnic speakers switching to Indo-European were involved in creating the Indo-European dialect we now know as Germanic.

Convergence of Finnic and Germanic

What both have in common is that the sound structures of Finnic and Germanic, which started from very different beginnings, apparently came to resemble one another significantly. If that is what we observe, we must conclude that both languages converged as a result of contact.

During the approximately five to six millennia that separate Proto-Uralic from Modern Finnish, there was only one episode during which the consonantal system underwent a dramatic overhaul. This episode separates the Finno-Saamic protolanguage, which is phonologically extremely conservative, from the Balto-Finnic protolanguage, which is very innovative.

finno-samic-consonants

By the time Finno-Saamic developed into Balto-Finnic, the consonant system was very different:

balto-finnic-consonants

In Balto-Finnic, the entire palatal series has been lost, apart from j, and the contrast between dentals and alveolars has disappeared: out of three different s-sounds only one remains. The fricatives ð and γ have been lost, and so has the velar nasal ŋ. The only increase has been in the number of long (geminate) consonants by the appearance of ss, mm, nn, and ll. The loss of separate alveolar and palatal series and the disappearance of ŋ could be conceived as convergences towards Proto-Germanic, which lacked such consonants. This is not obvious for the loss of the voiced fricatives γ, ð, which Proto-Germanic did possess. However, this way of comparing Balto-Finnic and Germanic is flawed in an important respect: what we are doing is assessing convergence by comparing the dynamic development from Finno-Saamic to Balto-Finnic to the static system of Proto-Germanic, as if Proto-Germanic is not itself the result of a set of changes to the ancestral Pre-Germanic consonantal system. If we wish to find out whether there was convergence and which language converged on which, what we should do, therefore, is to compare the dynamic development of Finno-Saamic to Balto-Finnic to the dynamic development of Pre-Germanic to Proto-Germanic, because only that procedure will allow us to state whether Balto-Finnic moved towards Proto-Germanic, or Proto-Germanic moved towards Balto-Finnic, or both moved towards a third language. The Pre-Germanic consonantal system can be reconstructed as follows: 7

pre-germanic-proto-germanic-verner-s-law

The slashes in the second and third rows indicate the uncertainty about the Proto-Indo-European nature of the sounds involved. (…)

What resulted was the following Proto-Germanic consonant system:

proto-germanic-consonant-system

We are now in a better position to answer the question whether Proto-Germanic and Balto-Finnic have converged. Three striking developments affected both languages:

  • Both languages lost the palatalized series of consonants (apart from j), which in both languages became non-palatalized.
  • Both languages developed an extensive set of long (geminate) consonants; Pre-Germanic had none, while Finno-Saamic already had a few.
  • Both languages developed an h.

These similarities between the languages are considerable.

The idea that perhaps both languages moved towards a lost third language, whose speakers may have been assimilated to both Balto-Finnic and Germanic, provides a fuller explanation but suffers from the drawback that it shifts the full burden of the explanation to a mysterious ‘language X’ that is called upon only in order to explain the developments in Proto-Germanic and Balto-Finnic. That comes dangerously close to circular reasoning.

Verner’s Law in Pre-Germanic

As we have seen in the preceding section, Verner’s law is a sound change that affected originally voiceless consonants, so *p , t , k , kj , kw, s of the Pre-Germanic system. These normally became the Proto-Germanic voiceless fricatives *f, θ, h, h, hw, s, respectively. But if *p, t, k etc. were preceded by an originally unstressed syllable, Verner’s law intervened and they were turned into voiced consonants. Those voiced consonants merged with the series *bh, dh, gh of the Pre-Germanic system and therefore subsequently underwent all changes that the latter did, turning out as *b/v , *d/ð , g/γ in the Proto-Germanic system (that is, v, ð, γ after a vowel and b, d, g in all other environments in the word). When *s was affected by Verner’s Law, a new phoneme *z arose. In a diagram:

pre-germanic-verner-s-law

While it is very common in the history of European languages for stress to influence the development of vowels, it only very rarely affected consonants in this part of the world. Verner’s law is a striking exception. It resembles a development which, on a much larger scale, affected Finno-Saamic: consonant gradation.(…)

In all Finno-Saamic languages, rhythmic gradation has become phonemic and fossilized. The connection between rhythmic gradation and Verner’s law is relatively straightforward: both processes involve changing a voiceless consonant after an unstressed syllable. (…)

We can therefore repeat for Proto-Uralic the argument that persuaded us earlier that gradation in Saami and Balto-Finnic must go back to the common Finno-Saamic protolanguage: the similarity of the gradation rules in Nganasan to those in Finno-Saamic is so specific and so detailed, and the phenomenon of gradation so rare in the languages of the world, that gradation must be reconstructed for the Uralic protolanguage.

Verner’s law turns all voiceless obstruents (Pre-Germanic *p, t, k, kj, kw, s) into voiced obstruents (ultimately Proto-Germanic *b/v , d/ð, g/γ, g/γ, gw, z) after a Pre-Germanic unstressed syllable. Rhythmic gradation turns all voiceless obstruents after an unstressed syllable into weak-grade consonants, which means that *p, t, k, s become Finnic *b/v , d/ð , g/γ, z. This is striking. Given the geographical proximity of Balto-Finnic and Germanic and given the rare occurrence of stress-related consonant changes in European languages, it would be unreasonable to think that Verner’s law and rhythmic gradation have nothing to do with one another.

It is very hard to accept, however, that gradation is the result of copying Verner’s law into Finnic. First of all, Verner’s law, which might account for rhythmic gradation, in no way accounts for syllabic gradation in Finnic. And, second, gradation can be shown to be an inherited feature of Finnic which goes all the way back to Proto-Uralic. Once one acknowledges that Verner’s law and gradation are causally linked and that gradation cannot be explained as a result of copying Verner’s law into Finnic, there remains only one possibility: Verner’s law is a copy of Finnic rhythmic gradation into Germanic. That means that we have finally managed to find what we were looking for all along: a Finnic sound feature in Germanic that betrays that Finnic speakers shifted to Germanic and spoke Germanic with a Finnic accent. The consequence of this idea is dramatic: since Verner’s law affected all of Germanic, all of Germanic has a Finnic accent.

indo-european-uralic-bell-beaker-corded-ware-migrations
Late Chalcolithic migrations ca. 2600-2250 BC.

On the basis of this evidence for Finnic speakers shifting to Germanic, it is possible to ascribe other, less specifically Finnic traits in Germanic to the same source. The most obvious trait is the fixation of the main stress on the initial syllable of the word. Initial stress is inherited in Finno-Saamic but was adopted in Germanic only after the operation of Verner’s law, quite probably under Finnic influence. The consonantal changes described in section V.3.1 can be attributed to Finnic with less confidence. The best case can be made for the development of geminate (double) consonants in Germanic, which did not inherit any of them, while Finno-Saamic inherited *pp, tt, kk, cc and took their presence as a cue to develop other geminates such as *nn and *ll . Possibly geminates developed so easily in Proto-Germanic because Finnic speakers (who switched to Germanic) were familiar with them. Other consonantal changes, such as the loss of the palatalized series in both Germanic and Balto-Finnic and the elimination of the different s- and c-phonemes, might have occurred for the same reason: if Balto-Finnic had undergone them earlier than Germanic, which we do not know, they could have constituted part of the Balto-Finnic accent in Germanic. An alternative take on those changes starts from the observation that they all constitute simplifications of an older, richer system of consonants. While simplifications can be and often are caused by language shift if the new speakers lacked certain phonemes in their original language, simplifications do not require an explanation by shift: languages are capable of simplifying a complex system all by themselves. Yet the similarities between the simplifications in Germanic and in Balto-Finnic are so obvious that one would not want to ascribe their co-occurrence to accidental circumstances.

Grimm’s Law in Proto-Germanic (speculative)

Voiceless lenis pronunciation of b, d, g is typical of the majority of German and Scandinavian dialects, so may well have been inherited from Proto-Germanic. Voiceless lenis is also the pronunciation that has been assumed to underlie the weak grades of Finno-Saamic single *p, t, k. If Proto-Germanic *b, d, g were indeed voiceless lenis, the single most striking result of the Germanic consonant shift is that it eliminated the phonological difference between voiced and voiceless consonants that Germanic had inherited from Proto-Indo-European (…) Since neither Finno-Saamic nor Balto-Finnic possessed a phonological difference between voiced and voiceless obstruents, its loss in Proto-Germanic can be regarded as yet another example of a Finnic feature in Germanic.

grimms-law

It is clear that this account of the first Germanic consonant shift as yet another example of Finnic influence is to some degree speculative. The point I am making is not that the Germanic consonant shift must be explained on the basis of Finnic influence, like Verner’s law and word-initial stress, only that it can be explained in this way, just like other features of the Germanic sound system discussed earlier, such as the loss of palatalized consonants and the rise of geminates.

A consequence of this account of the origins of the Proto-Germanic consonantal system is that the transition from Pre-Germanic to Proto-Germanic was entirely directed by Finnic. Or, to put it in less subtle words: Indo-European consonants became Germanic consonants when they were pronounced by Finnic speakers.

post-bell-beaker-europe
Post-Bell-Beaker Europe, after ca. 2200 BC.

The vocalic system, on the other hand, presented less difficulties for both, Indo-European and Uralic speakers, since it was quite similar.

Schrijver goes on to postulate certain asymmetric differences in loans, especially with regard to Proto-Germanic, Balto-Finnic, Proto-Saamic, Proto-Baltic, and later contacts, including a potential non-Uralic, non-IE substrate language to justify some of these, which may in turn be connected with Kroonen’s agricultural substrate hypothesis of Proto-Germanic, and thus also with the other surviving Scandinavian Neolithic cultures before the eventual simplification of the cultural landscape during the Bronze Age.

Conclusion on the origin of Germanic

The Finnic-Germanic contact situation has turned out to be of a canonical type. To Finnic speakers, people who spoke prehistoric Germanic and its ancestor, Pre-Germanic, must have been role models. Why they were remains unclear. In the best traditions of Uralic–Indo-European contacts, Finnic speakers adopted masses of loanwords from (Pre-)Germanic. Some Finnic speakers even went a crucial step further and became bilingual: they spoke Pre-Germanic according to the possibilities offered by the Finnic sound system, which meant they spoke with a strong accent. The accent expressed itself as radical changes in the Pre-Germanic consonantal system and no changes in the Pre-Germanic vowel system. This speech variety became very successful and turned an Indo-European dialect into what we now know as Germanic. Bilingual speakers became monolingual speakers of Germanic.

What we do not know is for how long Finnic-Germanic bilingualism persisted. It is possible that it lasted for some time because both partners grew more alike even with respect to features whose origin we cannot assign to either of them (loss of palatalized consonants): this suggests, perhaps, that both languages became more similar because generally they were housed in the same brain. What we can say with more confidence is that the bilingual situation ultimately favoured Germanic over Finnic: loanwords continued to flow in one direction only, from Germanic to Finnic, hence it is clear that Germanic speakers remained role models.

This is as far as the linguistic evidence can take us for the moment.

Based on archaeology and genetics, I think we can say that the close North-West Indo-European – Proto-Finnic interaction in Scandinavia lasted for hundreds of years, during the time when a unifying Nordic culture and language developed from Bell Beaker maritime elites dominating over Corded Ware groups.

As we know, Uralic languages were in close contact with Middle PIE, and also later with Proto-Indo-Iranian. This Pre-Germanic development in Scandinavia is therefore another hint at the identification of a rather early Proto-Finnic spoken in the Baltic area – potentially then by Battle Axe groups – , and thus the general identification of Uralic expansion with the different Corded Ware groups.

NOTE. The ‘common’ loss of certain palatals, which Schrijver interprets as a change of Pre-Germanic from the inherited Proto-Indo-European, may in fact not be such – in the opinion of bitectalists, including us, and especially taking the North-West Indo-European reconstruction and the Corded Ware substrate hypothesis into account – , so this effect would be a rather unidirectional shift from Finnic to Germanic. On the other hand, certain palatalization trends which some have described for Germanic could in fact be explained precisely by this bidirectional influence.

Related:

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:

Minimal Corded Ware culture impact in Scandinavia – Bell Beakers the unifying maritime elite

copper-age-late-bell-beaker

Chapter The Sea and Bronze Age Transformations, by Christopher Prescott, Anette Sand-Eriksen, and Knut Ivar Austvoll, In: Water and Power in Past Societies (2018), Emily Holt, Proceedings of the IEMA Postdoctoral Visiting Scholar Conference on Theories and Methods in Archaeology, Vol. 6.

NOTE. You can download the chapter draft at Academia.edu.

Abstract (emphasis mine):

Along the western Norwegian coast, in the northwestern region of the Nordic Late Neolithic and Bronze Age (2350–500 BCE) there is cultural homogeneity but variable expressions of political hierarchy. Although new ideological institutions, technology (e.g., metallurgy and boat building), intensified agro‑pastoral farming, and maritime travel were introduced throughout the region as of 2350 BCE, concentrations of expressions of Bronze Age elites are intermittently found along the coast. Four regions—Lista, Jæren, Karmøy, and Sunnmøre—are examined in an exploration of the establishment and early role of maritime practices in this Nordic region. It is argued that the expressions of power and material wealth concentrated in these four regions is based on the control of bottlenecks, channels, portages, and harbors along important maritime routes of travel. As such, this article is a study of prehistoric travel, sources of power, and maritime landscapes in the Late Neolithic and Early Bronze Age of Norway.

Interesting excerpts:

(…)The [Corded Ware culture (CWC)] in Norway (or Battle Axe Culture, 2750–2400/2350 BCE) is primarily represented in Eastern Norway, with a patchy settlement pattern along the Oslo fjord’s coast through the inland valleys to Trøndelag in Central Norway (Hinsch 1956). The CWC represents an enigmatic period in Norwegian prehistory (Hinsch 1956; Østmo 1988:227–231; Prescott and Walderhaug 1995; Shetelig 1936); however the data at the moment suggests the following patterns:

  • Migration: The CWC was the result of a small‑scale immigration, but did not trigger substantial change.
  • Eastern and limited impact: The CWC was primarily located in small settlement patches in eastern Norway.
  • Terrestrial: In terms of maritime practices, the CWC does not represent a significant break from older traditions, though it seems to have a more pronounced terrestrial bearing. It is conceivable that pastures and hunting grounds were a more important political‑economic resource than waterways.

The mid‑third millennium in Norway, around 2400 BCE, represents a significant reorientation. Bell Beaker Culture (BBC) settlements in western Denmark and Norway archaeologically mark the instigation of the Nordic LN, though much of the historical process leading from the Bell Beaker to the Late Neolithic, 2500 to 2350 BCE, remains unclear (Prescott 2012; Prescott and Melheim 2009; Prieto‑Martinez 2008:116; Sarauw 2007:66; Vandkilde 2001, 2005). Still, the outcome is the establishment of the Nordic region of interaction in the Baltic, Northern Germany, Sweden, Denmark, and Norway. The distribution of artifact materials such as Bell Beakers and flint daggers attests to the far‑flung network of regular exchange and communication. This general region of interaction was reproduced through the Late Neolithic and Bronze Age.

nordic-late-neolithic
The Nordic region in the Late Neolithic and Bronze Age. Sites and regions discussed in the text are marked (ater Prescott and Glørstad 2015:fig. 1).

The transition from the preceding Neolithic period hunter‑gatherer societies was rapid and represents a dramatic termination of hunter‑gatherer traditions. It has been argued that the transformation is tied to initial migrations of people to the western coast of Norway from BBC areas, possibly from northern Jutland (Prescott 2011; Prescott and Walderhaug 1995:273). Bifacial tanged‑and‑barbed points, often referred to as “Bell Beaker points,” probably represent an early, short phase of the BBC‑transition around 2400 BCE. In Norway these points have a predominantly western and coastal distribution (Østmo 2012:64), underscoring the maritime nature of the initial BBC‑expansion.

late-neolithic-flint-daggers
Distribution routes for LN1 flint daggers type 1 suggesting communication routes and networks. (Redrawn after fig. 9, Apel 2001:17).

(…) In response to the question about what attracted people from Bell Beaker groups to western Norway, responses have hypothesized hunting products, political power, pastures, and metals. Particularly the latter has been emphasized by Lene Melheim (2012, 2015:37ff).

A recent study by Melheim and Prescott (2016) integrated maritime exploration with metal prospecting to explain initial excursions of BBC‑people along the western coast and into the fjords. Building on the archaeological concept of traveling metal prospectors as an element in the expansion of the Bell Beaker phenomenon, in combination with anthropological perspectives on prospecting, the article explores how prospecting for metal would have adjusted to the landscapes of western Scandinavia. Generally speaking, prospecting seldom leads to successful metal production, and it is difficult to study archaeologically. However, it will often create links between the prospectors’ society and indigenous groups, opening new territories, and have a significant transformative impact—on both the external and indigenous actors and societies.

While the text echoes the traditional idea that Corded Ware spread Indo-European languages, Prescott (since Prescott and Walderhaug 1995) is a supporter of the formation of a Nordic community and a Nordic (i.e. Pre-Germanic) language with the arrival of Bell Beakers.

An identification of the Corded Ware language as of a previous Proto-Indo-European stage is possible, as I have previously said (although my preference is Uralic-related languages).

This CWC language would thus still form the common substrate to both Germanic and Balto-Slavic, both being North-West Indo-European dialects, which spread with Bell Beakers over previous Corded Ware territory.

NOTE. This pre-LPIE nature could be in turn related to Kortlandt’s controversial proposal of an ealier PIE dative *-mus shared by both branches. However, that would paradoxically be against Kortlandt’s own assumption that the substrate was in fact of a non-Indo-European nature

See also:

On Latin, Turkic, and Celtic – likely stories of mixed societies and little genetic impact

celtic-europe-national-geographic

Recent article on The Conversation, The Roman dead: new techniques are revealing just how diverse Roman Britain was, about the paper (behind paywall) A Novel Investigation into Migrant and Local Health-Statuses in the Past: A Case Study from Roman Britain, by Redfern et al. Bioarchaeology International (2018), among others.

Interesting excerpts about Roman London:

We have discovered, for example, that one middle-aged woman from the southern Mediterranean has black African ancestry. She was buried in Southwark with pottery from Kent and a fourth century local coin – her burial expresses British connections, reflecting how people’s communities and lives can be remade by migration. The people burying her may have decided to reflect her life in the city by choosing local objects, but we can’t dismiss the possibility that she may have come to London as a slave.

The evidence for Roman Britain having a diverse population only continues to grow. Bioarchaeology offers a unique and independent perspective, one based upon the people themselves. It allows us to understand more about their life stories than ever before, but requires us to be increasingly nuanced in our understanding, recognising and respecting these people’s complexities.

We already have a more or less clear idea about how little the Roman conquest may have shaped the genetic map of Europe, Africa, or the Middle East, in contrast to other previous or later migrations or conquests.

Also, on the Turkic expansion, the recent paper of Damgaard et al. (Nature 2018) stated:

In the sixth century AD, the Hunnic Empire had been broken up and dispersed as the Turkic Khaganate assumed the military and political domination of the steppes22,23. Khaganates were steppe nomad political organizations that varied in size and became dominant during this period; they can be contrasted to the previous stateless organizations of the Iron Age24. The Turkic Khaganate was eventually replaced by a number of short-lived steppe cultures25 (…).

We find evidence that elite soldiers associated with the Turkic Khaganate are genetically closer to East Asians than are the preceding Huns of the Tian Shan mountains (Supplementary Information section 3.7). We also find that one Turkic Khaganate-period nomad was a genetic outlier with pronounced European ancestries, indicating the presence of ongoing contact with Europe (…).

turk-medieval-populations
Analyses of Turk- and Medieval-period population clusters. a, PCA of Tian Shan Hun, Turk, Kimak, Kipchack, Karakhanid and Golden Horde, including 28 individuals analysed at 242,406 autosomal SNP positions. b, Results for model-based clustering analysis at K = 7. Here we illustrate the admixture analyses with K = 7 as it approximately identifies the major component of relevance (Anatolian/ European farmer component, Caucasian ancestry, EHG-related ancestry and East Asian ancestry).”

These results suggest that Turkic cultural customs were imposed by an East Asian minority elite onto central steppe nomad populations, resulting in a small detectable increase in East Asian ancestry. However, we also find that steppe nomad ancestry in this period was extremely heterogeneous, with several individuals being genetically distributed at the extremes of the first principal component (Fig. 2) separating Eastern and Western descent. On the basis of this notable heterogeneity, we suggest that during the Medieval period steppe populations were exposed to gradual admixture from the east, while interacting with incoming West Eurasians. The strong variation is a direct window into ongoing admixture processes and the multi-ethnic cultural organization of this period.

We already knew that the expansion of the La Tène culture, associated with the expansion of Celtic languages throughout Europe, was probably not accompanied by massive migrations (from the IEDM, 3rd ed.):

The Mainz research project of bio-archaeometric identification of mobility has not proven to date a mass migration of Celtic peoples in central Europe ca. 4th-3rd centuries BC, i.e. precisely in a period where textual evidence informs of large migratory movements (Scheeres 2014). La Tène material culture points to far-reaching inter-regional contacts and cultural transfers (Burmeister 2016).

Also, from the latest paper on Y-chromosome bottleneck:

[The hypothesis of patrilineal kin group competition] has an added benefit in that it could explain the temporal placement of the bottleneck if competition between patrilineal kin groups was the main form of intergroup competition for a limited episode of time after the Neolithic transition. Anthropologists have repeatedly noted that the political salience of unilineal descent groups is greatest in societies of ‘intermediate social scale’ (Korotayev47 and its citations on p. 2), which tend to be post-Neolithic small-scale societies that are acephalous, i.e. without hierarchical institutions48. Corporate kin groups tend to be absent altogether among mobile hunter gatherers with few defensible resource sites or little property (Kelly49 pp. 64–73), or in societies utilizing relatively unoccupied and under-exploited resource landscapes (Earle and Johnson50 pp. 157–171). Once they emerge, complex societies, such as chiefdoms and states, tend to supervene the patrilineal kin group as the unit of intergroup competition, and while they may not eradicate them altogether as sub-polity-level social identities, warfare between such kin groups is suppressed very effectively51,52.These factors restrict the social phenomena responsible for the bottleneck to the period after the initial Neolithic but before the emergence of complex societies, which would place the bottleneck-generating mechanisms in the right period of time for each region of the Old World.

chalcolithic_late_Europe_Bell_Beaker
Diachronic map of Late Copper Age migrations including Classical Bell Beaker (east group) expansion from central Europe ca. 2600-2250 BC

However, I recently read in a forum for linguists that the expansion of East Bell Beakers overwhelmingly of R1b-L21 subclades in the British Isles “poses a problem”, in that it should be identified with a Celtic expansion earlier than traditionally assumed…

That interpretation would be in line with the simplistic maps we are seeing right now for Bell Beakers (see below for the Copenhagen group).

If anything, the results of Bell Beaker expansions (taken alone) would seem to support a model similar to Cunliffe & Koch‘s hypotheses of a rather early Celtic expansion into Great Britain and Iberia from the Atlantic.

invasion-from-the-steppe-yamnaya
Spread of Indo-European languages (by the Copenhagen group).

But it doesn’t. Mallory already explained why in Cunliffe & Koch’s series Celtic from the West: the Bell Beaker expansion is too early for that; even for Italo-Celtic. It should correspond to North-West Indo-European speakers.

Not every population movement that is genetically very significant needs to be significant for the languages attested much later in the region.

This should be obvious to everyone with the many examples we already have. One of the least controversial now would probably be the expansion of R1b-DF27, widespread in Iberia probably at roughly the same time as R1b-L21 was in Great Britain, and still pre-Roman Iberians showed a mix of non-Indo-European languages, non-Celtic languages (at least Galaico-Lusitanian), and also some (certain) Celtic languages. And modern Iberians speak Romance languages, without much genetic impact from the Romans, either…

It is well-established in Academia that the expansion of La Tène is culturally associated with the spread of Celtic languages in Europe, including the British Isles and Iberia. While modern maps of U152 distribution may correspond to the migration of early Celts (or Italo-Celtic speakers) with Urnfield/Hallstatt, the great Celtic expansion across Europe need not show a genetic influence greater than or even equal to that of previous prehistoric migrations.

post-bell-beaker-europe
Post-Bell-Beaker Europe, after ca. 2200 BC.

You can see in these de novo models the same kind of invented theoretical ‘problem’ (as Iosif Lazaridis puts it) that we have seen with the Corded Ware showing steppe ancestry, with Old Hittite samples not showing EHG ancestry, or with CHG ancestry appearing north of the Caucasus but no EHG to the south.

However you may want to explain all these errors in scientific terms (selection bias, under-coverage, over-coverage, faulty statistical methods, etc.), these interpretations were simply fruit of the lack of knowledge of the anthropological disciplines at play.

Let’s hope the future paper on Celtic expansion takes this into consideration.

Related: