From the wealth of fossil evidence, it’s clear that modern humans first evolved in Africa. But for a while the timing of this event was unclear. Can all modern humans, Homo sapiens, date their ancestry to early hominins in Africa that migrated out and spread around the world about 2 million years ago? Or did the groups that left Africa ultimately go extinct, so that modern humans evolved from a group of hominins in Africa that migrated out much more recently? Molecular studies helped to answer this question.