Genomic Variation in Seven Khoe-San Groups Reveals Adaptation and Complex African History

The history of click-speaking Khoe-San, and African populations in general, remains poorly understood. We genotyped ∼2.3 million SNPs in 220 southern Africans and found that the Khoe-San diverged from other populations ≥100,000 years ago, but structure within the Khoe-San dated back to about 35,000 years ago. Genetic variation in various sub-Saharan populations did not localize the origin of modern humans to a single geographic region within Africa; instead, it indicated a history of admixture and stratification. We found evidence of adaptation targeting muscle function and immune response, potential adaptive introgression of UV-light protection, and selection predating modern human diversification involving skeletal and neurological development. These new findings illustrate the importance of African genomic diversity in understanding human evolutionary history.