Ancient DNA and the Indo-European Question, Yet Again
In a recent blog post on Diversity Linguistics blog entitled “Ancient DNA and the Indo-European Question”, Paul Heggarty of the Max Planck Institute for Evolutionary Anthropology (Leipzig) reviews two genetics articles, just published in Nature (a preprint version of the Haak et al. article was discussed in my earlier post):
- Haak, W. et al. [David Reich’s group, Harvard] 2015. (online since 2015-03-01) Massive migration from the steppe was a source for Indo-European languages in Europe. Nature 522 (7555): 207–211.
- Allentoft, M.E. et al. [Eske Willerslev’s group, Copenhagen] 2015. Population genomics of Bronze Age Eurasia. Nature 522 (7555): 167–172.
Heggarty summarizes the contributions of these two papers with respect to the Indo-European question as follows:
Both papers interpret their results as leaning towards the Steppe hypothesis, albeit rather tentatively and superficially in places. On closer inspection, indeed, all is by no means so clear cut. The new data actually turn out to be equally compatible, if not more so, with the Steppe as the immediate origin of just a few branches of Indo-European (notably Balto-Slavic and perhaps Tocharian). These Bronze Age movements would thus be only secondary to an original Neolithic expansion of the Indo-European family as a whole, with farming, out of the northern arc of the Fertile Crescent (i.e. the ‘Anatolian’ hypothesis).
What follows is a detailed analysis of what the articles actually show and how it relates to the question of the Indo-European homeland. In some respects, I agree with Heggarty and in others I strongly disagree. Most importantly, Heggarty and I concur that while the two genetics papers offer evidence of westward migration of people from the Pontic steppes to Europe, they fail to provide “closure” on the issue of “the origins of Indo-European [which] has eluded us ever since linguistic science began, when Sir William Jones first posed this very question in 1786”, as Heggarty puts it. He notes further that the genetic studies ask (or answer?) the “wrong Indo-European question”: whether there was a population movement from the Yamnaya culture area to that of the Corded Ware culture rather than whether the Indo-European language family can be associated with that movement. Consequently, geneticists are able to support the archeological findings that there were at least two major migration waves that peopled Europe: Neolithic farmers from the Near East and horse-riding warriors from the steppes, separated by about 2,500 years. It should be noted, however, that the two genetics papers, especially the one by Haak et al., provide only a modest summary of how their results can be interpreted in the context of the Indo-European problem; they do not advertise themselves as offering a “closure” or even “decisive support” for the Steppe theory. Considering how certain scholars in the field have trumpeted their own results (with the help of popular media!), such restraint must be respected.
Where Heggarty and I disagree most strenuously is on what the results of the genetic studies can tell us about the Indo-European controversy. Heggarty maintains that the genetic findings are perfectly compatible “with the steppe movements they uncover being part of a secondary phase of expansion, which may well have further spread a few branches of Indo-European (plus some Uralic) into north-eastern Europe, and perhaps Tocharian eastwards — but only after most of the rest of the family had spread earlier with farming” (aka the Anatolian theory). I, however, think that it is just as erroneous to tie the spread of Indo-European languages to Neolithic farmers as to the “Kurgan” steppe dwellers based solely of genetic evidence. Simply put, genes do not speak. Genetic evidence can tell us about migration of people, but not spread of languages because genes do not always move with languages (see my earlier posts here and here). Heggarty addresses this issue in Addendum 1, at the end of his post; he writes:
But hold on: can’t languages also spread ‘culturally’, through prestige, without migrations of people? In the modern world, a majority of human languages are already heading for extinction as their speakers shift en masse to other languages. But this is an abrupt reversal: a collapse and disappearance of the language diversity arisen over the preceding millennia. It is driven by the revolutionary changes of the Modern Era: the nation state, language standardisation, printing, mass literacy and transport, telecommunications and now globalisation. Those are no valid model for deep Indo-European prehistory, when human populations were just tiny fractions of today’s, and societies radically different in scale.
But there are no solid reasons to believe that “elite dominance” or any other form of culturally mediated language shift is purely a modern phenomenon. For example, Forster and Renfrew (2011) show that language shift has been a common feature in the history of numerous gender-biased mixed communities around the world. Such communities typically arise when men come from elsewhere and marry—or enslave—local women; the resulting communities speak the language of the male newcomers rather than that of the local women. In genetic terms, the language spoken by such gender-biased mixed communities correlates better with Y-DNA than mtDNA. Forster and Renfrew’s examples include northern Russia, where Slavic-speaking men intermarried with Finnic-speaking women, with the resulting communities speaking Russian (see also also Malyarchuk et al. 2004); Iceland, whose population descends mostly from Norsemen intermarrying heavily with Irish women (see also Goodacre et al. 2005); Papua New Guinea coastal areas, where mixed communities consisting primarily of Austronesian men and local Papuan women speak Austronesian languages; and more. None of these cases—and others discussed by Forster and Renfrew—involve the trappings of the Modern Era listed by Heggarty: “the nation state, language standardisation, printing, mass literacy and transport, telecommunications”, etc. Thus, there are no reasons to believe that language shift, possibly of a gender-biased kind, was not at the root of the Indo-European expansion. In this context, the relatively significant impact of Neolithic mtDNA on the present-day European gene pool, which Heggarty refers to in connection with Brandt et al.’s (2013) article, need not be interpreted as evidence for the Neolithic/Anatolian origins of Indo-European.
Another issue that is highly problematic for the proponents of the Anatolian theory concerns the “wheel words”. As I have explained in my earlier post, the availability of cognates involving wheels and other aspects of wheeled vehicles, as well as horses, across a broad range of Indo-European languages, especially in branches that were the earliest to veer off the rest of the family tree—Anatolian and Tocharian—implies that speakers of Proto-Indo-European knew horses and used wheeled vehicles. As discussed in detailed in David W. Anthony’s excellent book, The Horse, the Wheel, and Language, the earliest pieces of archeological evidence of horse and wheel date to 3500 BCE (or 5,500 years ago). Because agricultural expansion from Anatolia occurred several millennia earlier, Neolithic farmers cannot be associated with Proto-Indo-European.
Heggarty takes up this issue in Addendum 2, where he claims that “the supposed ‘wheel’ words actually go back to more general words for turn, rotate and walk, formed into words that look literally like ‘turn-turn (thing)’, for example”. In this respect, the Indo-European “wheeled” vocabulary, he claims, is exactly like the word mouse, which acquired a new sense in computing in English, then this new sense was “borrowed” (or more precisely, calqued) into other European languages, resulting in German Maus, Dutch muis, and Russian myš all acquiring this new meaning more than a thousand years after the languages split. In our recently published book The Indo-European Controversy: Facts and Fallacies in Historical Linguistics, Martin W. Lewis and I argue against this “calquing” analysis of the Indo-European “wheel” words, drawing heavily on the work of Don Ringe (cf. Ringe 2006 and chapter 8 of Pereltsvaig and Lewis 2015). Rather than being a result of horizontal transmission, the “wheel words” of Indo-European are true cognates.
To summarize, I agree with Heggarty that Haak et al. and Allentoft et al. provide only weak evidence for the Steppe theory, but I dispute his claim that these genetic studies offer stronger evidence in favor of the Anatolian alternative. I think genetics can tell only part of the Indo-European story, furnishing evidence of population movements, but not of language shift.
I would also like to use this opportunity to announce a course I will be offering at Stanford’s Continuing Studies Program in the Fall 2015, titled “The Science of the Deep Human Past: Linguistics, Genetics and Archeology”. In this multi-disciplinary team-taught course, we will examine novel techniques that shed new light on human populations long before recorded history. Geneticist Matthew Jobin, archeologist Michael Shanks, historical geographer Martin W. Lewis, linguist Johanna Nichols, and myself will provide students with an introduction to cutting-edge approaches to studying the distant past. The geographical focus of the course will be on Eurasia, a region whose prehistory is both intellectually captivating and ideologically charged. We will look at various groups that peopled the continent, including the Neolithic farmers who brought agriculture from the Near East into Europe, the waves of horse-riding warriors from the steppes who spread their Indo-European languages, and the diverse peoples who settled the Caucasus Mountains. By the end of the course, we aim to understand how to interpret and reconcile state-of-the-art findings from different disciplines into a coherent narrative. Check out Stanford CSP Fall Catalog or watch this space for further details!
Anthony, David W. (2007) The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World. Princeton, NJ: Princeton University Press.
Brandt, G., Haak, W., Adler, C.J., Roth, C., Szécsényi-Nagy, A., Karimnia, S., Möller-Rieker, S., Meller, H., Ganslmeier, R., Friederich, S., Dresely, V., Nicklisch, N., Pickrell, J.K., Sirocko, F., Reich, D., et al. (2013) Ancient DNA reveals key stages in the formation of Central European mitochondrial genetic diversity. Science 342 (6155): 257–261.
Forster, P. & C. Renfrew (2011) Mother Tongue and Y Chromosomes. Science 333 (6048): 1390.
Goodacre, S., A. Helgason, J. Nicholson, L. Southam, L. Ferguson, E. Hickey, E. Vega, K. Stefánsson, R. Ward & Bryan Sykes (2005) Genetic evidence for a family-based Scandinavian settlement of Shetland and Orkney during the Viking periods. Heredity 95: 129–135.
Malyarchuk, B.; M. Derenko, T. Grzybowski, A. Lunkina, J. Czarny, S. Rychkov, I. Morozova, G. Denisova, & D. Miścicka-Śliwka (2004) Differentiation of mitochondrial DNA and Y chromosomes in Russian populations. HumBio 877-900.
Pereltsvaig, Asya & Martin W. Lewis (2015) The Indo-European Controversy: Facts and Fallacies in Historical Linguistics. Cambridge University Press.
Ringe, Don (2006) Proto-Indo-European wheeled vehicle terminology. Unpublished Ms., University of Pennsylvania.
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