Beyond "Out of Africa"?

Paradigm shifts for the 21st century

Over the past few years, I’ve often been asked about the status of the “Out of Africa” theory of the origins of modern humans. I say “modern humans,” because our genus, Homo, humans in the broader sense, has been a presence across Africa and Eurasia for well over one million years. “Modern humans” simply refers to the lineage which contributed the vast majority of the ancestry to the people alive today. Additionally, it tends to correlate with particular characteristics, such as a high forehead and a flat face, at least in contrast with other famous groups of humans such as Neanderthals.

In the 1980's a group of geneticists and paleoanthropologists noticed patterns in the genetic and fossil data that might suggest all people outside of Africa derived from people inside of Africa. The genetic data showed that Africans were very diverse, and all populations outside of Africa could be nested within the African family tree. In this model, everyone from Spain to Australia to South America descends from a small group of modern humans who left Africa a bit over 50,000 years ago. The early models even suggested that the same dynamic occurred within Africa so that all humans descend from a small tribe.