Biochemistry and Molecular Biology

Permanent URI for this community

http://41.93.62.172:4000/handle/123456789/146

Browse

Browsing Biochemistry and Molecular Biology by Subject "African hunter-gatherers"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Evolutionary history and adaptation from high-coverage whole-genome sequences of diverse African hunter-gatherers.
    (Cell, 2012-08-03) Nyambo, Thomas B.
    To reconstruct modern human evolutionary history and identify loci that have shaped hunter-gatherer adaptation, we sequenced the whole genomes of five individuals in each of three different hunter-gatherer populations at >60× coverage: Pygmies from Cameroon and Khoesan-speaking Hadza and Sandawe from Tanzania. We identify 13.4 million variants, substantially increasing the set of known human variation. We found evidence of archaic introgression in all three populations, and the distribution of time to most recent common ancestors from these regions is similar to that observed for introgressed regions in Europeans. Additionally, we identify numerous loci that harbor signatures of local adaptation, including genes involved in immunity, metabolism, olfactory and taste perception, reproduction, and wound healing. Within the Pygmy population, we identify multiple highly differentiated loci that play a role in growth and anterior pituitary function and are associated with height.
  • Thumbnail Image
    Item
    Genomic evidence for shared common ancestry of East African hunting-gathering populations and insights into local adaptation.
    (Proceedings of the National Academy of Sciences, 2019-03-5) Nyambo, Thomas B.
    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.