and Eurasia, are no longer tenable. In 2016, my colleagues and I used an adaptation of the Li and Durbin method26 to compare populations from around the world to the earliest branching modern human lineage that has contributed a large proportion of the ancestry of a population living today: the one that contributed the lion’s share of ancestry to the San hunter-gatherers of southern Africa. Our study,27 like most others,28 found that the separation had begun by around two hundred thousand years ago
