人類学：サハラ以南の古代人は地元に根付いた生活をしていた

Sub-Saharan African foragers who lived towards the end of the Pleistocene epoch favoured a regional style of living, a Nature study of ancient human DNA suggests. The research, which doubles the time depth of ancient DNA reported from sub-Saharan Africa, sheds new light on the population history of Africa.

It has been difficult to decipher Africa’s ancient population history because the recent movements of pastoralists and farmers over the past 5,000 years have obscured more-ancient population structures. To probe deeper time, Mary Prendergast, David Reich and colleagues studied ancient genomic information from 34 different individuals, including 6 newly generated datasets from individuals from eastern and south-central Africa spanning the past 18,000 years. Three highly divergent source populations were identified; one from eastern Africa, one from southern Africa and a previously unappreciated lineage that today is found at its highest levels in foragers living in the rainforests of central Africa.

Previous studies, based on archaeology, have suggested that living became more regionalized towards the end of the Pleistocene. This genomic study provides additional evidence in favour of the hypothesis. The scenario that emerges is one in which people mixed and moved around between east, south and central Africa, around 50,000 years ago. This created a population structure that then remained highly stable towards the end of the Pleistocene, about 20,000 years ago, when people were living more regionally.