My own working hypothesis would derive the earliest Proto-Indo-Europeans with groups living in Neolithic eastern Anatolia and northern Mesopotamia. There are details to be fleshed out, such as when this group of people reached the Balkans (pending ancient DNA from the region), and how they interfaced with the populations living in the north of the Black and Caspian seas (e.g., via a trans-Caucasus movement or a counterclockwise spread around the Caspian).

The distribution for the root location lies in the region of Anatolia in present-day Turkey. To quantify the strength of support for an Anatolian origin, we calculated the Bayes factors (21) comparing the posterior to prior odds ratio of a root location within the hypothesized Anatolian homeland (11) (Fig. 1, yellow polygon) with two versions of the steppe hypothesis—the initial proposed Kurgan steppe homeland (6) and a later refined hypothesis (7) (Table 1). Bayes factors show strong support for the Anatolian hypothesis under a RRW model.

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As the earliest representatives of the main Indo-European lineages, our 20 ancient languages might provide more reliable location information. Conversely, the position of the ancient languages in the tree, particularly the three Anatolian varieties, might have unduly biased our results in favor of an Anatolian origin. We investigated both possibilities by repeating the above analyses separately on only the ancient languages and only the contemporary languages (which excludes Anatolian). Consistent with the analysis of the full data set, both analyses still supported an Anatolian origin (Table 1).

Despite support for an Anatolian Indo- European origin, we think it unlikely that agriculture serves as the sole driver of language expansion on the continent. The five major Indo-European subfamilies—Celtic, Germanic, Italic, Balto-Slavic, and Indo-Iranian—all emerged as distinct lineages between 4000 and 6000 years ago (Fig. 2 and fig. S1), contemporaneous with a number of later cultural expansions evident in the archaeological record, including the Kurgan expansion (5–7).





A new paper inuses Bayesian phylogeographic methods to model the spatial expansion of Indo-European languages from their Anatolian homeland. An informative video shows how the authors estimate the process took place across space and time:There is also a podcast with Q.D. Atkinson on the new study, as well as a website by the authors on their research; the FAQ/Controversies section seems particularly useful.I don't hold high hopes that, despite the mounting evidence , this will dissuade people from arguing for a steppe PIE origin. And, it shouldn't. Only a vigorous debate will resolve the issue conclusively. And, since IE languages appear on the archaeological record long after their split under any scenario, this may be one of those problems that will never be solved to everyone's satisfaction.I don't agree with all the details of the authors' model, but certainly they place the PIE homeland near to where I believe it was. Resistance to an Anatolian origin will become more convincing if adherents of different homeland solutions manage to put their ideas in quantitative form.As I wrote recently The current paper suggest a slightly different origin, in Southern Anatolia, perhaps influenced by the distribution of the historical Anatolian languages in the area when they were first put down in writing. But, I suspect that the transposition of Anatolian languages into the areas where they were first attested may have happened late in prehistory. In any case, whether the PIE homeland was in Southern or Eastern Anatolia, the results of this paper explicitly reject the Kurgan Pontic steppe hypothesis.From the paper:The West Asian origin of the Proto-Indo-Europeans makes excellent sense in the light of the genetic evidence . But, as I hint at the above paragraph, the tempo of their expansion into Europe remains to be clarified. I strongly suspect, on the basis of the Iceman and Swedish Neolithic TRB farmer ( Gok4 ) whose DNA has been published that theNeolithic was not Indo-European, because these individuals lack the "West Asian" autosomal component.But, when did the Indo-Europeans first set foot on Europe? Were they already present at the time of Dimini and Vinča in the Balkans? I tend to think that a reasonable proposition, because the 8.2 kiloyear event may have transposed a second set of Neolithic farmers into Europe, of Halafian origin. Or, did they appear later, during the Copper and Bronze Ages with the spread of metallurgy ? Until we get ancient DNA from the Balkans and Anatolia, we won't know for sure. But, Y-haplogroups J2, and R1 so conspicuously absent from Neolithic Europe down to 5ka (and in the case of J2, completely missing from the record altogether) must have entered Europe at some point. Did they take the fast train into Europe post-5ka, or did they lurk in both Anatolia and Europe pre-5ka? Thanks to the BEAN project we might find out.The idea that ~5ka something happened in Europe is also supported by the paper:So, while the deepest prehistory of Indo-European is firmly rooted in Anatolia during the early Neolithic, this is not inconsistent with something important happening in Europe during c. 5ka. But this was a secondary phenomenon, not the earliest seat of the Indo-Europeans. Also, I would not particularly relate this to the Kurgan expansion, but more probably to the arrival of metallurgical "guilds" with higher social complexity Both horses and wheeled vehicles quickly spread far and wide because of their simplicity and utility; if they were first adopted by a particular people, they quickly spread beyond it.As such, the people who invented it would have had a distinct advantage until their trade secrets were leaked, or too many Bronze weapons were in the hands of their enemies. During the Bronze Age, more and more people got access to weaponry, and by the end of it, wars were raging all across Western Eurasia.We tend to think ofNeolithic farmers, but it is quite likely that people kept coming into Europe since its initial colonization. After all, the people who came to the Americas in 1492 were the vanguard of many others who followed them. The same must have happened in Europe as well: a continuous process of settlement by various groups at different times, at least until the Bronze and Iron Ages when everyone, all over West Eurasia, seem to have become very quarrelsome and more than willing to use their swords, spears, axes, and arrows to dissuade newcomers who ventured into their territory.Coverage of the new paper elsewhere: NY Times 24 August 2012: Vol. 337 no. 6097 pp. 957-960 DOI: 10.1126/science.1219669Remco Bouckaert et al.There are two competing hypotheses for the origin of the Indo-European language family. The conventional view places the homeland in the Pontic steppes about 6000 years ago. An alternative hypothesis claims that the languages spread from Anatolia with the expansion of farming 8000 to 9500 years ago. We used Bayesian phylogeographic approaches, together with basic vocabulary data from 103 ancient and contemporary Indo-European languages, to explicitly model the expansion of the family and test these hypotheses.These results highlight the critical role that phylogeographic inference can play in resolving debates about human prehistory.