Some of the last surviving Neanderthals were remarkably diverse ‪—‬ suggesting inbreeding didn't doom them

Some of the last surviving Neanderthals displayed greater genetic diversity than scientists previously thought, a new study of ancient DNA reveals, challenging the idea that genetic decline was the main cause of their extinction.

Neanderthals were among the closest relatives of modern humans, with their lineages diverging around 500,000 years ago. Although Neanderthals once ranged across Eurasia, they are usually thought to have gone extinct about 40,000 years ago.

Much remains a mystery about why Neanderthals went extinct. Previous genetic analyses of DNA from Neanderthals in Siberia revealed that those groups lived in small, isolated communities with signs of frequent interbreeding between close relatives. This...