In Which population in the 1000 Genomes Project samples has the most Neandertal similarity? John Hawks publishes some figures showing how different populations from the 1000 Genomes Project are more/less similar to the Vindija Neandertal sequence. My most recent thoughts on the topic on Neandertal admixture can be found here.
The most important findings are the following:
First, Tuscans appear to have more shared derived variants with Vindija than Brits do. I can think of two explanations for this finding:
- Higher genetic diversity in southern Europe compared to northern Europe; if these shared variants occurred at a low frequency in southern Europe vs. northern Europe to begin with, then genetic drift would have driven more of them to extinction in the north than in the south.
- Possibility that the Vindija sequence has modern human admixture from a population of early Southern Europeans that would have contributed more to the gene pool of Tuscans (who are geographically quite close to Croatia) than to Brits
Second, North Chinese appear to be more similar to Neandertals than South Chinese are.
- I am not entirely sure whether genetic drift would work in this case, since presumably CHB is representative of a larger Chinese population than Chinese settlers in Singapore.
- A different explanation is that south Chinese may possess more admixture from an Asian type of erectus-like population that predates the common ancestor of modern humans and Neandertals, who almost certainly lived in the western end of Eurafrasian region.
Third, the Luhya from Kenya appear to have less Neandertal similarity than the Yoruba from Nigeria. This, of course, makes very little sense if Neandertal similarity can only be attributed to Neandertal admixture, since there were no Neandertals in Africa at all. Moreover, while the Luhya live in Kenya, their ultimate origins are further west, since they are a Bantu group, although they show mixed West/East African affiliations.
There are two alternatives:
- Modern humans did originate in North-West Africa as the Y-chromosome phylogeny suggests, and East Africans possess some distinctive Palaeo-African ancestry from before the sapiens-Neandertal common ancestor.
- Back-migration from Eurasia that affected different populations to different degrees; it is my impression, for example, that the Yoruba are almost completely a Y-haplogroup E population, but if anyone has any comparative results at hand, feel free to comment.