Tuesday 4 January 2011
Scientists have recovered the DNA code of a human relative recently discovered in Siberia, and it delivered a surprise: This relative roamed far from the cave that holds its only known remains.
By comparing the DNA to that of modern populations, scientists found evidence that these “Denisovans” from more than 30,000 years ago ranged all across Asia. They apparently interbred with the ancestors of people now living in Melanesia, a group of islands northeast of Australia. There’s no sign that Denisovans mingled with the ancestors of people now living in Eurasia, which made the connection between Siberia and distant Melanesia quite a shock.
Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, scientists have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group (named Denisovans) that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4-6% of its genetic material to the genomes of present-day Melanesians.
A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans.