Neanderthals lived in Europe and western Asia from at least around 430,000 years ago until around 40,000 years before present.

The high-quality nuclear genomes of four Neanderthals provided numerous insights into the diversity and population history of Neanderthals and their interactions with early modern humans.

The more recent Neanderthal from Croatia (45,000 years ago) showed higher genetic diversity and less evidence of recent inbreeding than do the older Neanderthals from Denisova and Chagyrskaya caves (120,000, approximately 110,000, and approximately 60,000 years ago) who lived in the easternmost part of the known Neanderthal range.
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“The late Neanderthals from northwestern Europe appear to have been part of a connected regional population, rather than small, isolated groups with frequent mating between close relatives.”

Although modern humans had arrived in the region by around 47,000 years ago, none of the Neanderthal genomes showed traces of recent human DNA.

“Our results add to a striking asymmetry,” Bossoms Mesa said.

“We repeatedly find Neanderthal ancestry in early modern humans, but so far, we have not found clear evidence of recent modern human ancestry in late Neanderthals.”

The scientists also tested the theory that Neanderthals were gradually weakened by accumulating genetic defects.

Comparing early and late Neanderthals, they found no meaningful increase in harmful mutations over time, undermining the notion that genetic deterioration drove their extinction.

What ultimately doomed the Neanderthals remains an open question.