New data tells the story of how Asians spread to the Americas
A GROUP OF ASIANS travelled to Siberia, crossed to Alaska and became the first humans to settle in America – but some of their descendants decided to make the long and perilous journey back to the area which is now China and Russia.
The story is revealed in ancient DNA from a woman’s skull found in China. It clearly shows she was related to the first Native Americans, but dates back 14,000 years.
The implication: her family went from Asia to America, but some members returned.
Scientists believe that between 20,000 and 15,000 years ago, a group of people from the east coast of China travelled to Siberia and settled in the area around the Bering Straits, the waters which now divide Asia from America.
Both temperature and sea levels fluctuated – but at one point the sea fell away, providing a land bridge. At the same time, there were one or two ice-free corridors leading through Alaska, one on the coast and one inland.
The people from Asia trekked down through the land corridor to the northern America, while another group likely travelled along the coast, eventually reaching South America.
This happened some 15,000 years before the Vikings (and Christopher Columbus) approached the Americas from Europe.
But some of the descendants of the pioneers turned around and headed back to Asia. (The waters didn’t rise to re-separate Asia and America until 11,000 to 10,000 years ago.)
How do we know all this?
Genetic analysis of a 14,000-year-old woman’s skull found in Yunnan province, south-west China, indicates that some of her family came from the land that became the Americas. The data was printed in the July 14 issue of Current Biology, an academic journal.
The woman has been given the name Mengzi Ren by the people who located it in a Yunnan archaeological resource called the Cave of the Red Deer.
Although the partial skull was found in 1989, specialists could not even confirm whether it belonged to a member of our species, homo sapiens sapiens, or a more archaic ancestor, such as a Denisovan.
However, for the first time, scientists have recently been able to extract DNA from the skull—which has revealed numerous secrets. The work was led by scientist Bing Su at the Kunming Institute of Zoology at the Chinese Academy of Sciences. “It was a really exciting moment,” Su told New Scientist magazine. “It is difficult to find ancient DNA in such a sample. After three years of trying to extract DNA from around 100 spots on the cranium, we found ancient DNA that we could sequence.”
This confirmed that Mengzi Ren was definitely a female human—but the surprise came when they noticed she was related to an ancient population in North America.
“This is the first time we have sequenced an ancient east Asian genome from the time when people were migrating into America, helping to confirm the east Asian ancestry of Native Americans,” Su told New Scientist.
Based on this genetic analysis, the researchers speculate that some of these ancestors of Native Americans may have travelled north along the coastline of present-day eastern China, as well as through the Japanese islands, before crossing into America from Siberia.
Tabita Hunemeier of the Institute of Evolutionary Biology, Spain, said there was some evidence that the first humans to enter the Americas divided, with one group staying put and another eventually returning to East Asia. “This could be an explanation for the presence of a relationship between Mengzi Ren’s ancestry and ancient Native Americans,” she told the journal.
“Next, the team plans to sequence more ancient human DNA by using fossils from southern East Asia, especially ones that predated the Red Deer Cave people,” Science Daily reported.
Main image at the top is a montage by Fridayeveryday