For generations, science told a tidy story: modern humans emerged from Africa and replaced the Neanderthals who came before them. Genetic evidence has quietly rewritten that account. Non-African people today carry between one and four percent Neanderthal DNA — a biological record of coexistence, interbreeding, and a boundary between species that was never as firm as we imagined. The Neanderthals did not simply vanish; in a meaningful sense, they became part of us.