Scientists have analyzed the DNA from a 90,000-year-old female bone fragment found in Siberia, according to The New York Times. It turns out the girl had a unique set of parents: her mother is a Neanderthal, but her father is from a unique species of humans called the Denisovans.
Denisovans were discovered in 2010 by researchers working in the cave where the bone fragment was found. Scientists have found hints of interbreeding between Neanderthals and the ancestors of modern humans, but this is clear evidence, according to The New York Times.
“They managed to catch it in the act — it’s an amazing discovery,” said Sharon Browning, a geneticist at the University of Washington quoted by The New York Times.
The team has nicknamed the individual “Denny,” according to Nature. This is the first child scientists have found that is the result of interbreeding.
Svate Pääbo, a paleogeneticist involved in the study, initially thought the findings were a mistake.
“I thought they must have screwed up something,” he said.
Before this discovery, the main evidence scientists had for interbreeding was from a 40,000-year-old human fossil that showed a genetic link to Neanderthals. That fossil showed there had been interbreeding between Neanderthals and the ancestors of modern humans sometime in the last four to six generations, according to Nature.
Denny’s bone fragment is only the fifth Denisovan fossil to be found.
Denisovans appeared later than Neanderthals. Scientists don’t know much about how Denisovans looked or how they acted. It does seem clear that when the two species of humans met, they frequently mated, according to Kelly Harris, a population geneticist at the University of Washington in Seattle.
“The number of pure Denisovan bones that have been found I can count on one hand,” she said, indicating that Neanderthal-Denisovan hybrids may have been common. Over time, though, the two species stayed genetically separate. This may be because the children of these pairings were infertile or had other genetic issues.
Pääbo thinks encounters between the two types of humans were rare. Most Neanderthal remains have been found in Europe and western parts of Asia, while Denisovans seem to have stayed close to home in Siberia. There is some overlap between the two populations in the Altai Mountains, but the population would have been limited.
“I think any Neanderthal that lived west of the Urals [a mountain range in western Russia and Kazakhstan] would never ever meet a Denisovan in their life, said Pääbo according to Nature.
Regardless of how her parents met, Denny is still a unique find.
“To find a first-generation person of mixed ancestry from these groups is absolutely extraordinary,” says population geneticist Pontus Skoglund in Nature.