Berkeley scientists just generated a pristine genome sequence of Neanderthal DNA—the most complete ever created—and what they found might gross you out. It might also blow your mind.
The DNA sequence came from a 50,000 year old Neanderthal bone, a woman's toe to be exact. The scientists compared it with DNA from modern humans as well as Denisovans, the Neanderthals' contemporaries and often their lovers too. The analysis revealed a new level of complexity in the family tree that connects Neanderthals, Denisovans and a recently discovered mystery human species with modern man.
It also revealed that Neanderthals like to have sex with their siblings. The woman whose toe bone was analyzed, research showed, was the daughter of a very closely related man and woman, likely half siblings. The dataset as a whole suggests that inbreeding was more popular among Neanderthals than modern humans.
We've long known, however, that interbreeding was popular with everybody. The new study, which will be published in Nature on Thursday, says Neanderthals and Denisovans interbred often and are very closely related. Modern humans participated in the interbreeding, too, though they fancied the Neanderthals more than the Denisovans. The researchers estimate 1.5 to 2.1 percent of non-African, modern day genomes can be traced to Neanderthals, while about 0.2 percent can be traced to Denisovans.
Inevitably, we are different, though we're still figuring out exactly how. The new research shows that at least 87 specific genes in the modern day human genome differ from those in Neanderthals and Denisovans. Maybe one of them explains why we won out in the great game of evolution.