Researchers in Malawi examine bone fragments whose DNA provided input into a significant study of African migration patterns. Photo New York Times.There is an interesting article in Cell, Reconstructing Prehistoric African Population Structure. The summary reads:
"We assembled genome-wide data from 16 prehistoric Africans. We show that the anciently divergent lineage that comprises the primary ancestry of the southern African San had a wider distribution in the past, contributing approximately two-thirds of the ancestry of Malawi hunter-gatherers 8,100–2,500 years ago and approximately one-third of the ancestry of Tanzanian hunter-gatherers 1,400 years ago. We document how the spread of farmers from western Africa involved complete replacement of local hunter-gatherers in some regions, and we track the spread of herders by showing that the population of a 3,100-year-old pastoralist from Tanzania contributed ancestry to people from northeastern to southern Africa, including a 1,200-year old southern African pastoralist. The deepest diversifications of African lineages were complex, involving either repeated gene flow among geographically disparate groups or a lineage more deeply diverging than that of the San contributing more to some western African populations than to others. We finally leverage ancient genomes to document episodes of natural selection in southern African populations"
The New York Times (21 September 2017) carried a useful story by Carl Zimmer, Clues to Africa’s Mysterious Past Found in Ancient Skeletons, which provides some useful supplementary material.