Four West African populations — Yoruba, Esan, Mende, and Gambian — derive 2 to 19% of their genetic ancestry from a yet-undiscovered species of archaic hominin that diverged before the split of modern humans and the ancestors of Neanderthals and Denisovans, according to new research from the University of California, Los Angeles. Durvasula & Sankararaman provide complementary lines of evidence for archaic introgression into four West...