Sex and fertility across a million years of human divergence

David Reich proposes an ancient mixture that raises questions about attraction and reproductive compatibility

Could two human lineages spend more than a million years apart and still produce descendants together?

David Reich’s new preprint, Hypothesis: A modern human range expansion ~300,000 years ago had a critical role in Neandertal origins, proposes a history in which a successful early human population expanded into Europe and Africa, mixing with different l…