A key period in human evolution wasn't in Africa – David Reich

Geneticist David Reich challenges the traditional "out of Africa" narrative by exploring the possibility that the human lineage resided in Eurasia during a critical evolutionary window between 2 million and 500,000 years ago. While sub-Saharan Africa remained central to human development for millions of years, the period transitioning from *Homo erectus* to the common ancestors of Neanderthals and Denisovans lacks definitive geographic certainty. Genetic evidence reveals complex branching and archaic DNA contributions in Eurasia that are currently absent from the African record, partly due to better DNA preservation in cooler climates. Reich argues that Africa and Eurasia likely functioned as a single interconnected population with frequent gene flow, as geographic barriers were negligible over vast timescales. Understanding the "braided" nature of modern human ancestry now requires securing ancient DNA from Africa dating back 500,000 years to map how various archaic lineages eventually converged.