Monday, June 9, 2014

New Ancient DNA Results Galore

Ancient DNA from the Altai region, often a West Eurasian-East Eurasian border, shows a mix of West Eurasian and East Eurasian genetics in a number of individuals from ca. 2742 BCE to ca. 914 BCE.  Uniparental DNA isn't quite so definitive on the existence of admixture, but the autosomal data in every case where it is available, indicates a significant minority of Asian admixture.

Another large sample of ancient DNA from the Russian Steppe from 1000 BCE to 7000 BCE, shows a major transition from older samples representing typical European hunter-gatherers before 4000 BCE, followed by a transition to a population with significant "Ancestral Northern European" ancestry.

Another conference paper used maize genetics (some from ancient maize samples) to document the path of diffusion of this New World domesticated crop through the Americas.  (Gambler's House, meanwhile, has a nice post on the light shed by oral history on the ancestry and migration history of the Pueblo people of the American Southwest, addressing difficult issues of how to deal with "legendary history."  The migration purportedly starts with a volcanic eruption, tsunami and earthquake to the Southeast of the Four Corners area providing an archaeological recognizable event to search for to corroborate the story.)  A conference paper using a similar methodology uses the genetics of TB, which appears contrary to earlier conventional wisdom to have pre-Neolithic origins, to track human origins and migrations, which tends to corroborate important outlines of models of human migrations from other sources.

Another new ancient DNA study favors a maritime route via Cyprus and the Aegean, over an Anatolian route for the source of the Neolithic colonists who gave rise to the LBK and CP first wave archaeological cultures:
Sixty-three skeletons from the Pre Pottery Neolithic B (PPNB) sites of Tell Halula, Tell Ramad and Dja'de El Mughara dating between 8,700–6,600 cal. B.C. were analyzed, and 15 validated mitochondrial DNA profiles were recovered. In order to estimate the demographic contribution of the first farmers to both Central European and Western Mediterranean Neolithic cultures, haplotype and haplogroup diversities in the PPNB sample were compared using phylogeographic and population genetic analyses to available ancient DNA data from human remains belonging to the Linearbandkeramik-Alföldi Vonaldiszes Kerámia and Cardial/Epicardial cultures. We also searched for possible signatures of the original Neolithic expansion over the modern Near Eastern and South European genetic pools, and tried to infer possible routes of expansion by comparing the obtained results to a database of 60 modern populations from both regions. Comparisons performed among the 3 ancient datasets allowed us to identify K and N-derived mitochondrial DNA haplogroups as potential markers of the Neolithic expansion, whose genetic signature would have reached both the Iberian coasts and the Central European plain. Moreover, the observed genetic affinities between the PPNB samples and the modern populations of Cyprus and Crete seem to suggest that the Neolithic was first introduced into Europe through pioneer seafaring colonization.
The study also documents the significant shifts between the Pre Pottery Neolithic population of the Northwestern Fertile Crescent and its current population genetics.  On the other hand, one should not read too much into conclusions based on a sample of just 15 ancient mtDNA haplogroup assignments.

1 comment:

andrew said...

Corroborating the PPNB paper is another paper arguing for the same maritime route for the Neolithic colonization of Europe.