Fossil sheds light on mysterious ancient kin
Research reveals Denisovans travelled from Siberia to China
Nearly 40 years after it was found by a monk in a Chinese cave, a fossilised chunk of jawbone has been revealed as coming from a mysterious relative of the Neanderthals.
Until now, the only known remains of these Denisovans were a few scraps of bone and teeth recovered in a Siberian cave.
DNA from those fossils showed kinship with Neanderthals, but the remains disclosed little else.
The new discovery was made in the Baishiya Karst Cave, roughly 2,300km to the southeast in the Gansu province of China.
The right half of a jawbone with teeth is at least 160,000 years old, scientists reported on Wednesday in the journal Nature.
No DNA could be found, but scientists recovered protein fragments that they compared to the Siberian DNA showing that the fossil came from a Denisovan.
The find addresses several mysteries. One was why the Siberian DNA indicated that Denisovans were adapted to living at high altitudes when the Siberian cave is relatively close to sea level.
The Chinese cave, by contrast, is on the high-altitude Tibetan Plateau, about 3,280m high.
“Now we have an explanation,” said Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Germany, one of the paper’s authors.
In fact, “it is a big surprise” that any human relative could live in the cold climate and thin air of the plateau at that time, over 100,000 years before our own species showed up there, he said.
Previous research had indicated that Denisovans must have lived somewhere other than Siberia as traces of their DNA can be found in several present-day populations of Asia and Australia whose ancestors probably didn’t pass through that region.
The new finding expands their known range, though Hublin said it is still not clear where Denisovans first appeared. They are named for Siberia’s Denisova cave, where the remains were found.
The new work was a long time in coming. The monk who found the fossil in 1980 gave it to a Buddhist leader, who passed it along to Lanzhou University in China. Study of it began in 2010.
The discovery also provides new anatomical details that can be compared to other fossils from China, some of which are “good candidates for being Chinese Denisovans,” Hublin said.
Experts unconnected to the research agreed that the fossil could help identify other remains as Denisovan.
“We always assumed ... that Denisovans were distributed all across Asia,” said Bence Viola of the University of Toronto.
The Nature paper noted similarities to a fossil jaw reported in 2015 that had been dredged off the coast of Taiwan. So maybe the Denisovan range could be extended that far south, he said. — AP