Northern Africa could also have housed the source population for living humans

Abstract

Henn et al. (1) analyzed genetic diversity in extant African populations, including hunter-gatherers, and showed that indigenous hunter-gatherers in the Kalahari Desert have the longest population history, extending to 40,000 y ago or before. From this, Henn et al. (1) concluded that the source population for modern humans, including the group that expanded from Africa to Eurasia roughly 60,000 y ago, resided in southern Africa. There is the complication, however, that the dramatic climatic fluctuations of the late Pleistocene forced population redistributions, and this means that the ancestors of historic Kalahari hunter-gatherers could have lived elsewhere in Africa 60,000 y ago. They might subsequently have spread to replace preexisting southern Africans just as they spread to replace the Neanderthals and other preexisting Eurasians.