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As anatomically modern humans (AMH) migrated out of Africa and around the rest of the world, they met and interbred with multiple extinct hominid species. The traces of genetic input from these past interbreeding events, recorded in the genomes of modern populations, have created a powerful record of recent human migrations. The first of these events occurred between Neandertals, and a small group of AMH shortly after they left Africa, somewhere in western Eurasia around 55-50 ka, and left a genomic signal of about 2% Neandertal DNA that was subsequently spread across the rest of the world. In contrast to the Neandertals, the interbreeding events with other extinct hominid groups – such as the Denisovans, the east Eurasian sister group of Neandertals – remain poorly understood, but are potentially far more complex.
This manuscript was submitted to PeerJ Preprints as an Opinion article.