Neanderthal DNA is quite rare. Most of the samples we have are from women. But a deep dive into what male DNA is available shows that the Y chromosome from Neanderthal men came to resemble that of modern men more than that of Denisovans, another group of extinct humans that lived in the same era. This implies that when modern humans mated with Neanderthals, eventually the Neanderthal Y chromosome was pretty much wiped out.
The Y chromosome data—the first from Denisovans and the first high-coverage from Neanderthals—suggest that earlier Neanderthals had a Denisovan-like Y chromosome, but that this was replaced by the Y chromosome of modern humans after Neanderthals interbred with them between 370,000 and 100,000 years ago.
“It’s a really a great surprise,” says Mikkel Heide Schierup, an evolutionary biologist at Aarhus University who did not participate in the study but wrote an accompanying commentary. Only a few percent of the rest of the Neanderthal genome appears to be made up of modern human DNA, yet this study found that three different Neanderthal individuals, unearthed at sites spread across Eurasia and dating to periods tens of thousands of years apart, all carried modern human–like Y chromosomes. This suggests the widespread replacement of the Y across the Neanderthal population, he explains. “It’s a pretty dramatic event.”
There is now speculation that the modern human Y chromosome may have had some advantage in survival or reproduction. The Neanderthals suffered from a low population compared to other human species, which may have multiplied harmful mutations. Read about the study at TheScientist. -via Smithsonian
(Image credit: Paul Hermans)