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Wednesday, February 17, 2016

Mystery archaic admixture in Africans


Behind a paywall at Genome Research:

Comparisons of whole-genome sequences from ancient and contemporary samples have pointed to several instances of archaic admixture through interbreeding between the ancestors of modern non-Africans and now extinct hominids such as Neanderthals and Denisovans. One implication of these findings is that some adaptive features in contemporary humans may have entered the population via gene flow with archaic forms in Eurasia. Within Africa, fossil evidence suggests that anatomically modern humans (AMH) and various archaic forms coexisted for much of the last 200,000 yr; however, the absence of ancient DNA in Africa has limited our ability to make a direct comparison between archaic and modern human genomes. Here, we use statistical inference based on high coverage whole-genome data (greater than 60×) from contemporary African Pygmy hunter-gatherers as an alternative means to study the evolutionary history of the genus Homo. Using whole-genome simulations that consider demographic histories that include both isolation and gene flow with neighboring farming populations, our inference method rejects the hypothesis that the ancestors of AMH were genetically isolated in Africa, thus providing the first whole genome-level evidence of African archaic admixture. Our inferences also suggest a complex human evolutionary history in Africa, which involves at least a single admixture event from an unknown archaic population into the ancestors of AMH, likely within the last 30,000 yr.

Hsieh et al., Model-based analyses of whole-genome data reveal a complex evolutionary history involving archaic introgression in Central African Pygmies, Genome Research, Published in Advance February 17, 2016, doi: 10.1101/gr.196634.115

4 comments:

Karl_K said...

I found the following article very helpful for understanding this African Mystery Admixture.

http://tinyurl.com/hb23vqr

Davidski said...

Thanks Karl, never knew that existed.

Karl_K said...

No problem. I really think that a lot of people could benefit from that knowledge.

Even those of us at well-funded scientific institutes occasionally have trouble understanding a paper because of these types of issues.

Unknown said...

Are there a large population of people with this admixture. I have 17% of this admixture in my DNA. I want to find out really what this means, and is this common in 2017?