This is the blog for GW students taking Human Evolutionary Genetics. This site is for posting interesting tidbits on: the patterns and processes of human genetic variation;human origins and migration; molecular adaptations to environment, lifestyle and disease; ancient and forensic DNA analyses; and genealogical reconstructions.

GWHEG figure

GWHEG figure

Friday, February 14, 2020

The complete mitochondrial genome of the central chimpanzee, Pan troglodytes troglodytes





By analyzing 75 complete genomes from Pan, researchers were able to gain more information about gene flow between ancient populations of bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), something that has not been supported in the past due to a lack of high-coverage genomes. The two species are believed to have split sometime between 1.5-2.1 million years ago. This analysis included samples from 10 African countries, and included chimpanzee genomes from all three subspecies of chimpanzees (eastern, central, and western). To determine the extent to which genetic information can identify geographic location, researchers sequenced chromosome 21 from several eastern and central chimpanzees. They were able to identify the country and region of the country each chimpanzee came came from, and mentioned how this will be extremely useful in rehoming confiscated victims of the pet trade. They also found evidence for gene flow between chimpanzee subspecies, and that central, eastern, and Nigeria-Cameroon chimpanzees had a far greater number of shared alleles with bonobos than western chimpanzees. Derived alleles that were frequent in the bonobo genome were shared much more with central chimpanzees when compared to western chimpanzees, lending support to the idea that alleles that are more frequent are more likely to be shared. This suggests that ancient bonobo and eastern and central chimpanzee populations were able to share genes, approximately 200,000-550,000 years ago, and these also spread into Nigera-Cameroon chimpanzees. Thus, it seems admixture was occurring at low levels during Pan evolution, and this analysis provides more information and context on a complicated evolutionary history between sister species and subspecies.

https://science.sciencemag.org/content/354/6311/477.full.pdf+html?casa_token=5Fbnc3jY6y8AAAAA:78815iP4QNJ4TKJHj7E1BpLs43g38ei602NXU83nPrx355t1Q6kmw4snzEBAD_Bn-MpA1K003Xj5rg 
Rachel Nelson, February 18th Potluck

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