Just what makes a European?
European genetic ancestry used to seem straightforward and in general is now understood as an admixture of three sources; indigenous European hunter-gatherers from 42,00 to 45,000 ago, Middle Easterners from the agricultural revolution 10,000 years ago, and Central Asians who charged through Europe in the last 4,000 to 5,000 years. Last month, a paper in Nature, suggested at each entity entered Europe by way of a separate migrations and only coalesced in the last 5,000 years. A new study published in yesterday’s Science changes this suggestion.
This new study is based on ancient DNA extracted from the fossilized skeleton, Kostenki 14 or K-14, who once was a short, dark featured man from approx. 36,000 years ago who died along the Middle Don River in Kostenki-Borshchevo, Russia. The team extracted 13 samples from the arm bone. The DNA was sequenced to a final coverage of 2.42x. That is relatively low and means on average each nucleotide site was read 2.4 times. Thus, the sequence is likely to include a large number of errors and gaps… This does make it the second oldest whole human genome sequenced, here was the first.
From the sequence data, aside from dark features, he also had about 1% more Neandertal DNA than do Europeans and Asians today. This confirms what another, even older human from Siberia had shown — that humans and Neandertals mixed early, before 45,000 years ago, perhaps in the Middle East. Analysis of his DNA shows he has genes from all three of those migratory groups and so was already “pure European,” by modern standards says evolutionary biologist Eske Willerslev of the Natural History Museum of Denmark at the University of Copenhagen, who led the analysis. K-14 shared genetic ancestry with hunter-gatherers in Europe—as well as with the early farmers, suggesting that his ancestors interbred with members of the same Middle Eastern population who later turned into farmers and came to Europe themselves. Finally, he also carried the signature of the shadowy western Asians, including a boy who lived 24,000 years ago at Mal’ta in central Siberia. If that finding holds up, the mysterious DNA from western Eurasia must be very ancient, and not solely from a wave of nomads that entered Europe 5,000 years ago or so, as proposed by researchers in September.
His study suggests that Europeans today are the descendants of a very old, interconnected population of hunter-gatherers that had already spread throughout Europe and much of central and western Asia by 36,000 years ago. Willerslev predicts that after modern humans spread out of Africa about 60,000 years ago, they met Neandertals and interbred with them, perhaps in the Middle East. Then while one branch headed east toward Melanesia and Australia, another branch of this founder population, a.k.a, “basal Eurasians” and spread north and west into Europe and central Asia.
K-14 shares very few of the genetic hallmarks and variants associated with East Asian & Native American populations, and suggests that East Asians and Eurasians diverged early and may even have engaged in separate migrations of Africa or the Middle East. I know last year there was the analysis of MA-1, found in the Altai region of Siberia which showed Native American genetic affinities and might suggest there was a large overlap between Eurasians and East Asia but MA-1 could be a rare exception Taken together, the Nature paper from last month and yesterday’s Science paper suggests a time frame of about 9,000 years in which the two genetic populations, Europeans & Eastern Asians, diverged and that Europeans are descent is very old and very complicated.