Genomic evidence for shared common ancestry of East African hunting-gathering populations and insights into local adaptation.
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Date
2019-03-5
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Proceedings of the National Academy of Sciences
Abstract
Anatomically modern humans arose in Africa ∼300,000 years ago,
but the demographic and adaptive histories of African populations
are not well-characterized. Here, we have generated a genome-
wide dataset from 840 Africans, residing in western, eastern,
southern, and northern Africa, belonging to 50 ethnicities, and
speaking languages belonging to four language families. In addi-
tion to agriculturalists and pastoralists, our study includes 16 popula-
tions that practice, or until recently have practiced, a hunting-
gathering (HG) lifestyle. We observe that genetic structure in Africa
is broadly correlated not only with geography, but to a lesser extent,
with linguistic affiliation and subsistence strategy. Four East African
HG (EHG) populations that are geographically distant from each
other show evidence of common ancestry: the Hadza and Sandawe
in Tanzania, who speak languages with clicks classified as Khoisan;
the Dahalo in Kenya, whose language has remnant clicks; and the
Sabue in Ethiopia, who speak an unclassified language. Addition-
ally, we observed common ancestry between central African rain-
forest HGs and southern African San, the latter of whom speak
languages with clicks classified as Khoisan. With the exception of
the EHG, central African rainforest HGs, and San, other HG groups
in Africa appear genetically similar to neighboring agriculturalist or
pastoralist populations. We additionally demonstrate that infec-
tious disease, immune response, and diet have played important
roles in the adaptive landscape of African history. However, while
the broad biological processes involved in recent human adaptation
in Africa are often consistent across populations, the specific loci
affected by selective pressures more often vary across populations.
Description
Keywords
African hunter-gatherers, African diversity, Population genetics
Citation
Scheinfeldt, L.B., Soi, S., Lambert, C., Ko, W.Y., Coulibaly, A., Ranciaro, A., Thompson, S., Hirbo, J., Beggs, W., Ibrahim, M. and Nyambo, T., 2019. Genomic evidence for shared common ancestry of East African hunting-gathering populations and insights into local adaptation. Proceedings of the National Academy of Sciences, 116(10), pp.4166-4175.