We've always loved the ones we were with
Ancient bones point to Native Americans' twin ancestry
In the "Out of Africa" theory, Homo sapiens left their ancestral home in east Africa around 50,000 years ago, heading north, west and south. Their East Asian descendants eventually crossed from Sibera to Alaska, island-hopping across the frozen Bering Strait, around 15,000 years ago.Mystery humans spiced up ancients’ rampant sex lives
Thus began human settlement of modern-day North America, according to this thinking.
But a new study suggests this human odyssey is rather more complex, and just as compelling. Against all expectations, DNA teased from the bones of a child who lived in Siberia 24,000 years ago shows that the forerunners of Native Americans can also be traced to western Eurasia, or on the western boundaries of Asia.
"The result came as a complete surprise to us," said Eske Willerslev, a professor at the Centre for GeoGenetics in Denmark, who led the probe. Who would have thought that present-day Native Americans, who we learned in school derive from East Asians, share recent evolutionary history with western Eurasians?"
The ancient genomes, one from a Neanderthal and one from a different archaic human group, the Denisovans, were presented on 18 November at a meeting at the Royal Society in London. They suggest that interbreeding went on between the members of several ancient human-like groups living in Europe and Asia more than 30,000 years ago, including an as-yet unknown human ancestor from Asia.Perhaps you've had that date?
“What it begins to suggest is that we’re looking at a ‘Lord of the Rings’-type world — that there were many hominid populations,” says Mark Thomas, an evolutionary geneticist at University College London who was at the meeting but was not involved in the work.
All humans whose ancestry originates outside of Africa owe about 2% of their genome to Neanderthals; and certain populations living in Oceania, such as Papua New Guineans and Australian Aboriginals, got about 4% of their DNA from interbreeding between their ancestors and Denisovans, who are named after the cave in Siberia’s Altai Mountains where they were discovered. The cave contains remains deposited there between 30,000 and 50,000 years ago.
The meeting was abuzz with conjecture about the identity of this potentially new population of humans. “We don’t have the faintest idea,” says Chris Stringer, a paleoanthropologist at the London Natural History Museum, who was not involved in the work.
Labels: Mother nature