Out of the agricultural hearths

By Razib Khan | December 12, 2011 2:34 pm

Dienekes has an important post up, The womb of nations: how West Eurasians came to be. He outlines a scenario where a rapid expansion of a farming population has overlain much of Western Eurasia, atop aboriginal substrata. A few years ago you’d have laughed at such a model, mostly due to the authority of archaeologists and phylogeographers relying on mtDNA lineage distributions. No longer. This is not necessarily an orthodoxy, and the details of the model vary, but here is my verbal rendering of the simplest scenario:

1) ~50 thousand years hybridization between Eurasian hominins and “Out of Africa”

2) ~40-10 thousand years before the present, crystallization of the Paleolithic order of human population structure, derived from groups seeded in the original migration

3) ~10 thousand to a few thousand years before the present, the Paleolithic order is replaced and assimilated by farmers expanding from a few hearths

Below the fold is a stylized tree representation of what I have in mind.


MORE ABOUT: Anthropology, Genetics
  • Onur

    I think the divergence between Old Europeans and Old West Asians, if there was ever such a divergence, is much later than the divergence between ASI and Old East Asians + Old Siberians. David Reich’s soon-to-be-published European paper may address these issues.

  • http://washparkprophet.blogspot.com ohwilleke

    Yowsers! Usually, diagrams are more clear than words, but in this case, the diagram is more information than my brain can handle in one chunk.

  • Matt

    Shame you’ve only got two dimensions to work with, since it confuses the Ethiopian-West Asian relationship a little (unless that’s actually mediated through Europeans)! That’s quite a compressed way to present that plausible model though.

    I think the divergence between Old Europeans and Old West Asians, if there was ever such a divergence, is much later than the divergence between ASI and Old East Asians + Old Siberians. Yeah.

    Not too sure about South East Asians getting any Australian component though. The South East Asians, in the supplementary data in the Metspalu paper (http://download.cell.com/AJHG/mmcs/journals/0002-9297/PIIS0002929711004885.mmc1.pdf), seem to have quite comparable FST to Papuans as Oroqen do – basically equal, which seems not possible to reconcile with a proto-Papuan contribution unless there is some unknown mystery meat pushing them away by an equal amount. And quite comparable FST with Han Chinese as Europeans have with West Asians. Although if you meant purely Maritime South East Asia, rather than Peninsular South East Asia, then that’s not something that paper says anything about!

    (Populations with South Asian elements (like Burmese, South Asians) and/or mixes of West Eurasian and East Eurasian elements, like Uyghurs, Hazara, seem to have reduced FST with Papuans and Melanesians in this data, for some reason).

  • http://www.eurasian-sensation.blogspot.com Eurasian Sensation

    Could a similar process have happened in the Americas, at least to some extent? Obviously there are different population dynamics there, with agriculture developing relatively later. But the same process happened independently in Africa (the Bantu expansion) so I’d be surprised if it didn’t in the New World.

  • Dwight E. Howell

    Repeated invasions by nomadic horse clans need to be factored in. I know it’s hard to try and factor in what was happening as these repeated waves of expansion hammered against the farmers but they were a major factor until guns stopped the waves.

  • Onur

    Whether there was ever a divergence between Old East Asians and Old Siberians and its time are far from clear too. I think it too, if happened, is much later than the divergence between ASI and Old East Asians + Old Siberians.

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This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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