Modern humans interbred with Neanderthals before they disappeared, and most people of non-African ancestry still carry roughly 1 to 4 percent Neanderthal DNA today — meaning part of the human populati

Key Points:

• A man who died in a Romanian cave about 40,000 years ago carried between six and nine percent Neanderthal DNA, the highest ever found in any human genome, indicating a Neanderthal ancestor only four to six generations back.
• Studies published in December 2024 dated the main Neanderthal-modern human gene flow event to about 47,000 years ago, continuing for roughly 7,000 years, showing a prolonged overlap between the species.
• Certain Neanderthal DNA segments were harmful and rapidly eliminated from modern human genomes, creating "Neanderthal deserts" where archaic DNA is absent, while other fragments related to immunity and metabolism persist and provide adaptive benefits.
• Modern non-African populations carry about one to two percent Neanderthal DNA, with East Asians having slightly more and also some Denisovan ancestry; these archaic genetic contributions influence traits like skin pigmentation and disease susceptibility.
• Although Neanderthals went extinct as a distinct population around 40,000 years ago, genetic evidence reveals they interbred with modern humans, leaving a legacy that continues in present-day genomes.