Ancient teeth point to earliest modern humans in southern China
Updated
Modern humans may have occupied southern China at least 30,000 years earlier than previously thought.
Archaeologists have found 47 Homo sapiens teeth closely resembling our own, dated from 80,000-120,000 years old, in a cave in Hunan province, according to a letter published today in Nature.
The discovery adds a new chapter to the story of modern human migration, suggesting that our genetic ancestors were not the first H. sapiens to populate east Asia.
Until now, the earliest fossil evidence of H. sapiensfurther east than the Arabian Peninsula was been dated at 40,000-50,000 years ago, from Northern China, Borneo, and Lake Mungo in southwest New South Wales.
While the researchers did not find any other human bones or stone tools at the Hunan province site, they did uncover a large number of teeth from other animals, including five extinct large mammals such as an ancient elephant and an ancestor of the giant panda.
Researchers said the discovery also showed modern humans were living in southern China 30,000-70,000 years earlier than they were found in Europe.
They suggested the slower migration of H. sapiensinto Europe may have been the result of competition with Neanderthals, which ultimately led to extinction of Neanderthals and the dominance of modern humans.
Lead researcher, Dr Wu Liu of the Chinese Academy of Sciences in Beijing said the team was planning to undertake a genetic analysis on the teeth in the hope that this would answer questions about possible genetic links between these ancient H. sapiens and us.
Unlikely these humans are genetically related to us
Human evolution expert Associate Professor Darren Curnoe from UNSW Australia said it was unlikely these earlier H. sapiens were genetically related to us.
Although the find is "very clear evidence" of an early migration of modern humans out of Africa, it "predates the genetic signal for the peopling of the planet," Professor Curnoe added.
Analysis of the rate of genetic change over time - the 'genetic clock' - tells us that our ancestors arrived in east Asia around 30,000-50,000 years ago, he said.
Other ancient human discoveries in Asia
"If we assume that the genetic clock is right, then ... the teeth that have been found would represent a population that probably didn't contribute genetically to living people in east Asia today."
These earlier H. sapiens were probably replaced by a later wave of migration from Africa that gave rise to contemporary human populations, he said.
This is not the first discovery of its kind for the region; an analysis by Professor Curnoe's team of teeth found 30 years ago in a neighbouring province suggested they could be 60,000-80,000 years old, and another group found similarly modern teeth from another cave in southern China.
"So we've now got three sites from south-west China - this one being the most comprehensively studied and the best example - [so] this is not likely to be an anomaly, this is likely to be correct," he said.
What is now needed is DNA or more fossil evidence, particularly skulls or jaws, to help determine the relationship between these earlier H. sapiens and our direct ancestors, said Professor Curnoe.
http://www.abc.net.au/news/2015-10-15/earliest-modern-humans-in-southern-china/6854486
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