According to a report in Discovery News, the as-of-yet-unnamed new human species represents the first time that a hominid has been described not from the structure of its fossilized bones, but from the sequence of its DNA.
Her mtDNA shows that X-Woman shared a common ancestor with Neanderthals and modern humans one million years ago, so X-Woman and her species likely migrated out of Africa 500,000 years before the ancestors of Neanderthals left Africa.
"So whoever carried this mtDNA out of Africa was a creature that was not on our radar screen before," co-author Svante Paabo told Discovery News.
The bone, probably from a child, was found at Denisova Cave in the Altai Mountains of southern Siberia.
None of them matched with the new sequence, but they revealed that the individual was a human that carried twice as many genetic differences as Neanderthals do with our species.
Based on archaeological finds from Denisova Cave, the researchers suspect X-Woman and her species, along with the Neanderthals and modern humans, hunted large game, such as woolly mammoths and woolly rhinos.
Ornaments dating to the period, such as bracelets, were also found in the cave.