Genetics and southern African history

Southern Africa’s past is constellated by a series of demographic events tracing back to the dawn of our species, approximately 300,000 years ago. The intricate pattern of population movements over the millennia contributed to creating an exceptional level of diversity, which is reflected by the high degree of genomic variability of southern African groups. Although a complete characterization of the demographic history of the subcontinent is still lacking, several decades of extensive research have contributed to shed light on the main events. Genetic and archaeological researches suggest that modern humans may have emerged as the result of admixture between different African groups, possibly including other Homo populations, challenging the common view of a unique origin of our species. Although details are still unknown, surveys suggest that long term resident populations (related to Khoe-San speakers) of the subcontinent may have emerged hundreds of thousand years ago, and have inhabited the area for at least five millennia. Population movements, and the introduction of new cultural features, characterize the history of southern Africa over the last five millennia and have had a dramatic impact on subcontinental genetic variability. Traces of these migrations can be identified using different genetic systems, revealing a complex history of adaptation to new selective pressures and sex-biased admixture. The historical events of the European colonization and the slave trade of the last millennium, and the emergence of new cultural groups, further increased the genomic variability of human populations in this region, one of the most genetically diverse in the world.