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

steppe-admixture

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

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

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

The answer by Haak et al.:

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

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

Klejn response to that:

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

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

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

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

Regarding the arguments of Kristiansen and colleagues:

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

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

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

Regarding the work of Heyd,

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

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

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

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

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

Related:

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

How to do modern phylogeography: Relationships between clans and genetic kin explain cultural similarities over vast distances

yakut-phylogeography

A preprint paper has been published in BioRxiv, Relationships between clans and genetic kin explain cultural similarities over vast distances: the case of Yakutia, by Zvenigorosky et al (2017).

Abstract:

Archaeological studies sample ancient human populations one site at a time, often limited to a fraction of the regions and periods occupied by a given group. While this bias is known and discussed in the literature, few model populations span areas as large and unforgiving as the Yakuts of Eastern Siberia. We systematically surveyed 31,000 square kilometres in the Sakha Republic (Yakutia) and completed the archaeological study of 174 frozen graves, assembled between the 15th and the 19th century. We analysed genetic data (autosomal genotypes, Y-chromosome haplotypes and mitochondrial haplotypes) for all ancient subjects and confronted it to the study of 190 modern subjects from the same area and the same population. Ancient familial links and paternal clan were identified between graves up to 1500 km apart and we provide new data concerning the origins of the contemporary Yakut population and demonstrate that cultural similarities in the past were linked to (i) the expansion of specific paternal clans, (ii) preferential marriage among the elites and (iii) funeral choices that could constitute a bias in any ancient population study.

Even if you are not interested in the cultural and anthropological evolution of this Turkic-speaking people of the Russian Far Eastern region, the method used is an excellent example of how to use archaeology and genetics (especially Y-DNA and mtDNA data) to obtain meaningful results when investigating ancient populations.

For quite some time, probably since the first renown admixture analyses of ancient DNA samples were published, we have been living under the impression that phylogeography, or simply archaeogenetics as it was called back in the day, is not needed.

Cavalli-Sforza’s assertion that the study of modern populations could offer a clear picture of past population movements is now considered wrong, and the study of Y-DNA and mtDNA haplogroups is today mostly disregarded as of secondary importance, even among geneticists. Whole genomic investigation (and especially admixture analyses) have been leading the new wave of overconfidence in genetic results, tightly joint with the ignorance of its shortcomings (and commercial interests based on desires of ethnic identification), and haplogroups are usually just reported with other, not entirely meaningful aspects of ancient DNA analyses.

While it is undeniable that admixture analyses are offering quite interesting results, they must be carefully balanced against known archaeological and linguistic knowledge. Phylogeography – and especially Y-DNA haplogroup assessment – is quite interesting in investigating kinship and clans in patrilocal communities – i.e. most communities in prehistoric and historic periods, unless proven otherwise.

Luckily enough, there are those researchers who still strive to obtain meaningful information from haplotypes. The article referenced in this post is quite interesting due to its phylogeographic method’s applicability to ancient cultures and peoples.

When some geneticists look at simplistic prehistoric maps, like those depicting Yamna, Afanasevo, Corded Ware, and Bell Beaker cultures together, they forget that 1) cultural regions are selected more or less arbitrarily (we only have certain scattered sites for each of these cultures); 2) economic or population contacts are difficult to ascertain and to represent graphically; and 3) time periods for archaeological sites are important – in fact, they are probably THE most important aspect in assessing how accurate a map (and its “arrows” of migration or exchange) represents reality.

A careful, detailed study like this one, if applied to the Pontic-Caspian steppe, would probably reveal how R1b subclades dominated steppe clans, beginning at least during the Suvorovo-Novodanilovka expansion to the west, and certainly representing the vast majority of lineages during the internal expansion in the Early Yamna period and its later expansion east and west of the steppe…

Featured image from the article, summing up Geography, Archaeology, and Genetics of Yakutia – including Y-DNA and mtDNA haplogroups from ancient populations.

Related:

Palaeogenomic and biostatistical analysis of ancient DNA data from Mesolithic and Neolithic skeletal remains

lepenski-vir-mesolithic-anatolia-neolithic

PhD Thesis Palaeogenomic and biostatistical analysis of ancient DNA data from Mesolithic and Neolithic skeletal remains, by Zuzana Hofmanova (2017) at the University of Mainz.
Abstract:

Palaeogenomic data have illuminated several important periods of human past with surprising im- plications for our understanding of human evolution. One of the major changes in human prehistory was Neolithisation, the introduction of the farming lifestyle to human societies. Farming originated in the Fertile Crescent approximately 10,000 years BC and in Europe it was associated with a major population turnover. Ancient DNA from Anatolia, the presumed source area of the demic spread to Europe, and the Balkans, one of the first known contact zones between local hunter-gatherers and incoming farmers, was obtained from roughly contemporaneous human remains dated to ∼6 th millennium BC. This new unprecedented dataset comprised of 86 full mitogenomes, five whole genomes (7.1–3.7x coverage) and 20 high coverage (7.6–93.8x) genomic samples. The Aegean Neolithic pop- ulation, relatively homogeneous on both sides of the Aegean Sea, was positively proven to be a core zone for demic spread of farmers to Europe. The farmers were shown to migrate through the central Balkans and while the local sedentary hunter-gathers of Vlasac in the Danube Gorges seemed to be isolated from the farmers coming from the south, the individuals of the Aegean origin infiltrated the nearby hunter-gatherer community of Lepenski Vir. The intensity of infiltration increased over time and even though there was an impact of the Danubian hunter-gatherers on genetic variation of Neolithic central Europe, the Aegean ancestry dominated during the introduction of farming to the continent.

Taking only admixture analyses using Yamna samples:

This increased genetic affinity of Neolithic farmers to Danubians was observed for Neolithic Hungarians, LBK from central Europe and LBK Stuttgart sample. Some post-Neolithic samples also proved to share more drift with Danubians, again samples from Hungary (Bronze Age and Copper Age samples and also Yamnaya and samples with elevated Yamnaya ancestry (Early Bronze Age samples from Únětice, Bell Beaker samples, Late Neolithic Karlsdorf sample and Corded Ware samples).

(…)

The results of our ADMIXTURE analysis for the dataset including also Yamnaya samples are shown in Figure S1c. The cross-validation error was the lowest for K=2. Supervised and unsupervised analyses for K=3 are again highly concordant. Early Neolithic farmers again demonstrate almost no evidence of hunter-gatherer admixture, while it is observable in the Middle Neolithic farmers. However, much of the Late Neolithic hunter-gatherer ancestry from the previous analysis is replaced by Yamnaya ancestry. These results are consistent with the results of Haak et al. who demonstrated a resurgence of hunter-gatherer ancestry followed by the establishment of Eastern hunter-gatherer ancestry.

Again, admixture results show that something in the simplistic Yamna -> Corded Ware model is off. It is still interesting to review admixture results of European Mesolithic and Late Neolithic genomic data in relation to the so-called steppe or yamna ancestry or component (most likely an eastern steppe / forest zone ancestry probably also present in the earlier Corded Ware horizons) and its interpretation…

yamna-ancestry-europe
Image composed by me, from two different images of the PhD Thesis. To the left: Supervised run of ADMIXTURE. The clusters to be supervised were chosen to best fit the presumed ancestral populations (for HG Motala and for farmers Bar8 and Bar31 and for later Eastern migration Yamnaya). To the Right: Unsupervised run of ADMIXTURE for the Anatolian genomic dataset with Yamnaya samples for K=8.

Discovered via Généalogie génétique

Another hint at the role of Corded Ware peoples in spreading Uralic languages into north-eastern Europe, found in mtDNA analysis of the Finnish population

corded-ware-migration-yamna

Open article at Scientific Reports (Nature): Identification and analysis of mtDNA genomes attributed to Finns reveal long-stagnant demographic trends obscured in the total diversity, by Översti et al. (2017).

Of special interest is its depiction of Finland’s past as including the expansion of Corded Ware population of mtDNA U5b1b2 (and probably Y-DNA R1a-M417 subclades), most likely Uralic speakers of the Forest Zone, to the north of the Yamna culture (where Late Proto-Indo-European was spoken).

A later expansion of other subclades – particularly Y-DNA N1c -, was probably associated with the later western expansion of the Eurasian Seima-Turbino phenomenon, and its current prevalence in Finnish Y-DNA haplogroups might have been the consequence of the population decline ca. 1500 BC, and later Iron Age population bottleneck (with the population peak ca. 500 AD) described in the article.

That would more naturally explain the ‘cultural diffusion’ of Finnic languages into invading eastern N1c lineages, a diffusion which would have been in fact a long-term, quite gradual replacement of previously prevalent Y-DNA R1a subclades in the region, as supported by the prevalent “steppe” component in genome-wide ancestry of Finns.

Therefore, there were probably no sudden, strong population (and thus cultural) changes associated with the arrival of N1c lineages, like the ones seen with R1a (Corded Ware / Uralic) and R1b (Yamna / Proto-Indo-European) expansions in Europe.

How the Saami fit into this scheme is not yet obvious, though.

Abstract:

In Europe, modern mitochondrial diversity is relatively homogeneous and suggests an ubiquitous rapid population growth since the Neolithic revolution. Similar patterns also have been observed in mitochondrial control region data in Finland, which contrasts with the distinctive autosomal and Y-chromosomal diversity among Finns. A different picture emerges from the 843 whole mitochondrial genomes from modern Finns analyzed here. Up to one third of the subhaplogroups can be considered as Finn-characteristic, i.e. rather common in Finland but virtually absent or rare elsewhere in Europe. Bayesian phylogenetic analyses suggest that most of these attributed Finnish lineages date back to around 3,000–5,000 years, coinciding with the arrival of Corded Ware culture and agriculture into Finland. Bayesian estimation of past effective population sizes reveals two differing demographic histories: 1) the ‘local’ Finnish mtDNA haplotypes yielding small and dwindling size estimates for most of the past; and 2) the ‘immigrant’ haplotypes showing growth typical of most European populations. The results based on the local diversity are more in line with that known about Finns from other studies, e.g., Y-chromosome analyses and archaeology findings. The mitochondrial gene pool thus may contain signals of local population history that cannot be readily deduced from the total diversity.

From its results:

In general, there appears to be two loose and largely overlapping clusters among the Finn-characteristic haplogroups: the first between 1,000–2,000 ybp and the second around 3,300–5,500 ybp. The age of the older cluster coincides temporally with the arrival of the Corded-Ware culture and, notably, the spread of agriculture in Finland. The arrival and spread of agriculture, temporally corresponding with the age estimates for most of the haplogroups characteristic of Finns, might be a sign of population size increase enabled by the new mode of subsistence, resulting in reduced drift and accumulation of genetic diversity in the population.

(…)

Another insight in the past population sizes in Finland is based on radiocarbon-dated archaeological findings in different time periods. These analyses suggest two prehistoric population peaks in Finland, the Stone Age peak (c. 5,500 ybp) and the Metal Age peak (~1,500 ybp). Both of these peaks were followed by a population decline, which appears to have reached its ebb around 3,500 ybp. These developments are not distinguishable in the BSPs. However, these ages correspond well to the two haplogroup age clusters described above. The presumably less severe Iron Age population bottleneck seen in the archaeological data, 1,500–1,300 ybp, temporally coincides with the population size reduction visible for the Finn-characteristic subhaplogroups.

Related:

Discovered via Eurogenes.

Preprint paper: Estimating genetic kin relationships in prehistoric populations, by Monroy Kuhn, Jakobsson, and Günther

erperstedt-corded-ware

A new preprint paper appeared some days ago in BioRxiv, Estimating genetic kin relationships in prehistoric populations, by researchers of the Uppsala University Jose Manuel Monroy Kuhn, Mattias Jakobsson, and Torsten Günther. Jakobsson and Günther. You might remember the last two from their work Ancient X chromosomes reveal contrasting sex bias in Neolithic and Bronze Age Eurasian migrations, whose results were said not to be replicable by Lazaridis and Reich (PNAS), something they denied pointing to the limitations of the current aDNA data (PNAS).

They propose a new, more conservative method to infer close relationships (in contrast with available methods, suitable for modern samples). They have implemented the method as a software program, called READ, which should work better with degraded samples (typical of ancient DNA) by reducing false positives – and having therefore more false negatives. Abstract:

Archaeogenomic research has proven to be a valuable tool to trace migrations of historic and prehistoric individuals and groups, whereas relationships within a group or burial site have not been investigated to a large extent. Knowing the genetic kinship of historic and prehistoric individuals would give important insights into social structures of ancient and historic cultures. Most archaeogenetic research concerning kinship has been restricted to uniparental markers, while studies using genome-wide information were mainly focused on comparisons between populations. Applications which infer the degree of relationship based on modern-day DNA information typically require diploid genotype data. Low concentration of endogenous DNA, fragmentation and other post-mortem damage to ancient DNA (aDNA) makes the application of such tools unfeasible for most archaeological samples. To infer family relationships for degraded samples, we developed the software READ (Relationship Estimation from Ancient DNA). We show that our heuristic approach can successfully infer up to second degree relationships with as little as 0.1x shotgun coverage per genome for pairs of individuals. We uncover previously unknown relationships among prehistoric individuals by applying READ to published aDNA data from several human remains excavated from different cultural contexts. In particular, we find a group of five closely related males from the same Corded Ware culture site in modern-day Germany, suggesting patrilocality, which highlights the possibility to uncover social structures of ancient populations by applying READ to genome-wide aDNA data.

The software READ applied to the 230 ancient European DNA data from Mathieson et al. (2015) was studied, with certain interesting results. For starters, this paper already supports the idea that the five German Corded Ware samples from Esperstedt were all related, thus further supporting to a certain extent the culture’s patrilocality and female exogamy practices:

Of particular interest was a group of five males from Esperstedt in Germany who were associated with the Corded Ware culture {a culture that arose after large scale migrations of males from the east. Around 50 Corded Ware burials, six of them stone cists, were excavated near Esperstedt in the context of road constructions in 2005. Characteristic Corded Ware pottery was found in the graves and all male individuals had been buried on their right hand site. Interestingly, the central individual of the group of related individuals (I1541) was buried in a stone cist approximately 700 meters from the graves of the other four individuals which were all close to each other. The close relationship of this group of only male individuals from the same location suggest patrilocality and female exogamy, a pattern which has also been found from Strontium isotopes at another Corded Ware site just 30 kilometers from Esperstedt and suggested for the Corded Ware culture in general. This represents just one example of how the genetic analysis of relationships can be used to uncover and understand social structures in ancient populations.

It is to be expected that improvement in such methods can help more accurately define certain samples, by inferring their precise subclades. For example, in the case of those relatives from Esperstedt – classified variously as R(xR1b), R1a, or R1a1 – one would be able to classify those related patrilineally to the most precise subclade: in this case, that of the sample I0104 (ca.2473-2348 BC), of subclade R1a1a1-M417.

However, errors are dependent on the quality of the ancient DNA recovered:

READ does not explicitly model aDNA damage and it only considers one allele at heterozygous sites. This implies that a careful curation of the data is required to avoid errors due to low coverage, short sequence fragments, deamination damage, sequencing errors and potential contamination. We recommend a number of well established filtering steps when working with low coverage aDNA data

Heyd, Mallory, and Prescott were right about Bell Beakers

yamna-migration

Sometimes it is fun to read certain “old” papers. I have recently re-read some important papers that predicted what we are seeing now in aDNA analysis with surprising accuracy:

Harrison & Heyd (2007): “We predict that future stable isotope and ancientDNA analyses of Beaker skeletal material will support our view that immigration played an important role in the Europe-wide Bell Beaker phenomenon”. – Duh, obvious, right? Wrong. Read the whole paper. It was already becoming a classic in the study of the Bell Beaker culture before the latest research on Bell Beaker aDNA, and it will be still more important from now on. There are different models for the Bell Beaker origin and expansion, and this was only one of them: we had the Dutch model, the radiocarbon date-based attempts to locate Bell Beakers in Iberia or North Africa,… I tried to highlight the best sentences from Heyd’s article to include them in my article, and I just couldn’t stop highlighting almost everything. It is surprising that 10 years ago Volker Heyd was predicting so much from such a limited amount of material, and with conflicting reports coming from everywhere, from palaeogenetics to radiocarbon dating. Not that today their chronology of Le Petit – Chasseur is accepted by all, but their general Bell Beaker and Yamna model has been clearly established as the most likely one with support from aDNA.

– Mallory in Celtic from the West 2 (2013), as the last of many to propose Bell Beaker as the vector of spread of Late Indo-European languages, but the first to relate it to North-West Indo-European: “The spread of Indo-European languages from Alpine Europe may have begun with the Beaker culture, presuming here a non-Iberian Beaker homeland (Rhineland, Central European) for that part of the Beaker phenomenon that was associated with an Indo-European language. While it is possible that IE language(s) spread with the Beaker phenomenon, it is questionable that this was associated with Proto-Celtic rather than earlier forms of Late Indo-European, at least part of which might be subsumed under the heading NW Indo-European. This is because the time depth of the dispersal of the Beakers is so great and the earliest attested Celtic languages are so similar (…)”. You might think that it is related to the Atlantic Indo-European theory favoured by Cunnliffe and Koch in the book… Wrong, he specifically dismisses a Neolithic spread of Indo-European, and a Calcholithic spread of Celtic languages as too early. You might also think that to publish that in 2013 has no merit, given the data. Wrong again. Just look at the trend among renown archaeologists – like Anthony (with Haak) and Kristiansen (with Allentoft) – trying to hop on the bandwagon of Corded Ware-driven Indo-European dispersal based on the “steppe admixture” proportion of recent genetic papers, and you realize he is going against the grain here.

Prescott and Walderhaug 1995 (as referred to in Prescott 2012): “The Bell Beaker period is the most, perhaps the only, reasonable candidate for the spread and final entrenchment of a common Indo-European language throughout Scandinavia (and not just Corded Ware core areas of southern and eastern Scandinavia), and particularly Norway”. Duh again? Not so fast. While Bell Beaker had been proposed before as a vector of Indo-European languages in Europe, the association with Germanic was far more controversial. Only the unifying Dagger Period was more clearly established as of Pre-Germanic nature, but it could be interpreted as of Corded Ware, Úněticean, or even early Neolithic origin, or a mix of them. Bell Beaker groups were never good candidates, if only because of the desire by some researchers to offer a romanticized (either more unifying or ancient) picture of a Germanic Northern Scandinavian homeland, explained as a culturally and genetically homogeneous group.

Their papers seem to state the obvious now that the latest aDNA samples are proving them correct, but it was far from clear years ago: remember the native European Basque-R1b – Uralic-N1c harmony disrupted by invasive Eurasian Indo-European-speaking warriors carrying R1a lineages from Yamna to Corded Ware? Well that is still a thing for some. And even today the most popular interpretation of the spread of Indo-European-speakers in Europe is based on the defined “steppe ancestry” proportion found in Corded Ware individuals, and a supposedly Yamna community formed by R1b-R1a lineages, which is obviously reminiscent of the identification of R1a lineages with Proto-Indo-Europeans based on the initial analysis of haplogroups in modern populations.

It is sad to imagine how much we would have improved in our knowledge, had we read their work with interest when it was necessary, and not now that we have most of the aDNA clues. Still sadder is to see people rely on genetic studies alone to derive today what are likely the wrong conclusions. Again.

I will end with a mea culpa. I hadn’t read those works; but even if I had, I would have stayed with the simpler, R1a-Corded Ware model of Indo-European dispersion. That oversimplification will remain in the different editions of our Grammar of Modern Indo-European as a permanent reminder. Simpler seems always better, and Cavalli-Sforza had famously asserted that ancient population movements could be solved with the study of the structure of modern populations. I think he was right, that we can in fact ascertain ancient population movements by studying modern populations if we include anthropological disciplines, but it is such a complex task – and geneticists have not shown a good grasp in (or interest for) Anthropology -, that it is nowadays clearly wrong to rely on modern population samples to derive conclusions about ancient populations, and we are better off studying ancient DNA samples in their context.

We were Back-to-the-Future-wrong, overestimating our potential in some aspects – like the results of researching modern DNA -, and underestimating it in others – like the potential changes that ancient DNA investigation could bring for anthropological disciplines. Just as we are wrong today in trusting the potential of admixture analysis to be self-explanatory, without a need for wide anthropological investigation (or even able to revolutionize archaeological and linguistic theories).

I hope to keep a more critical view of publications – especially the most popular ones – from now on.