Analysis of a bone fragment found in a Siberian cave from a young female who died 90,000 years ago has revealed she was half Neanderthal and half Denisovan.
The girl, thought to be aged around 13, is an example of interbreeding between now-extinct human groups.
She is the first first-generation individual of mixed ancestry from two distinct human groups to be discovered.
Most modern non-African humans have traces of Neanderthal DNA and some Asian populations have Denisovan DNA, showing that homo sapiens, Neanderthals and Denisovans interbred.
As Neanderthal populations spread eastwards they encountered Denisovans, and the girl in the cave, nicknamed Denny by researchers, is the result of mating between a Neanderthal mother and a Denisovan father.
Pontus Skoglund, population geneticist at the Francis Crick Institute, said: "To find a first-generation person of mixed ancestry from these groups is absolutely extraordinary. It's really great science coupled with a little bit of luck."
A fragment of one of Denny's long bones was found in the Siberian cave several years ago.
Previous tests had been able to establish sex and when she died.
The most recent analysis compared Denny's DNA to genomes of a Neanderthal and a Denisovan. Researchers found she had one set of chromosomes from each hominin.
Neanderthals
Currently earliest fossils of Neanderthals in Europe are dated at 430,000 years ago and thereafter Neanderthals expanded into southwest and Central Asia.
They died out around 40,000 years ago, possibly as a result of competition following the exodus of homo sapiens (modern humans) from Africa between 60,000 and 40,000 years ago, although DNA analysis shows interbreeding between the two species.
Denisovans
A now-extinct subspecies of archaic humans, Denisovans ranged from Siberia to southeast Asia.
They lived among and interbred with the ancestors of some modern humans with about 3% to 5% of the DNA of Melanesians and Aboriginal Australians and around 6% in Papuans deriving from Denisovans.
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Sky News
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