Various bloggers have been whispering about the finding for a couple of days now (it’s embargoed), but at last NPR has the story. Some researchers managed to find DNA on a 40,000-year-old pinky finger, and testing it led to some remarkable findings:
Whoever that finger belonged to was not a human like us. Nor was it a Neanderthal, the only other member of the human line known to be living in Europe at the time, according to research described in the journal Nature. . . .
Paabo says the DNA they already have does indicate that this Siberian stranger, along with humans and Neanderthals, evolved from some common ancestor that lived in Africa about a million years ago. “Whoever carried this mitochondrial genome out of Africa about a million years ago is some new creature that has not been on our radar screens so far,” he says.
Scientists know generally when this new hominid — as human ancestors are known — appeared on the scene by comparing the number of mutations in the DNA of humans, Neanderthals and the X-woman. Mutations occur in a population at a certain rate that can indicate how long they’ve evolved separately from a common ancestor.
Though Paabo can’t say if this was an unknown species on the human line, he can say the X-woman’s ancestors probably migrated from Africa a million years ago, well before modern humans evolved.