A clear example is family trees how DNA evolves, passing from generation to generation. But it also reveals clues to the complicated history of human migration. Take the indigenous peoples of the Americas. DNA evidence suggests that groups of Asians migrated to Beringia, the land and sea region between Russia and North America, around 20,000 years ago (perhaps much earlier) and then gradually reached the Americas in waves.
Now, new evidence suggests Native Americans may have also traveled back to North Asia. In a study published Thursday in the journal Current biologyan international group of scientists discovered an ancient Siberian hunter-gatherer society dating back thousands of years and that some other ancient Siberian peoples (as well as their descendants) have Native American ancestry.
Here is the background – Much of what we know about the ancient inhabitants of Siberia comes from both archaeological and genetic evidence. Two main ancestral groups are recognized throughout North Asia: the ancient North Eurasian, based on skeletal remains of a small child who died 24,000 years ago in south-central Siberia, and the ancient Northeast Asian ancestors, discovered from skeletal remains in the Russian The Far East goes back to the Neolithic period, which lasted from about 4300 BC to 2000 BC. There is also a third group of ancient Paleo-Siberians who share kinship with Native Americans living today, according to previous research.
However, this information was not enough to create a coherent family tree. The main reason for this is simply the limited amount of ancient DNA analyzed from the Altai region, a mountainous crossroads between Russia, China, Mongolia and Kazakhstan.
“We described a previously unknown population of hunter-gatherers in the Altai, already 7,500 years old, which is a mixture of two distinct groups that lived in Siberia during the last ice age,” says Cosimo Posth, a geneticist at the University of Tübingen and senior author of the study, said in press release. “The Altai hunter-gatherer group contributed to many modern and later populations in North Asia, showing how great was the mobility of these foraging communities.”
The authors write in the paper that there is a 12,000-year gap between what genomic history scientists have collected so far from the few ancient human remains archaeologists have been able to collect in recent years. This gap has led to questions about how ancient humans interacted with each other and what those interactions meant for their descendants, including Native American groups.
What’s new – The researchers analyzed DNA from the skeletal remains of ten 7,500-year-old individuals (the youngest from 5,500 years ago), obtained from three regions of North Asia: the Altai-Sayan region, which is located between the Altai and Sayan mountains in Inner Asia; Russian Far East, the easternmost part of Russia; and the Kamchatka Peninsula, surrounded on one side by the Bering Sea.
The researchers found that the DNA of these hunter-gatherers was unique, resulting from a mix of Paleo-Siberian and ancient North Eurasian ancestry. These individuals may have been ancestral to other groups in North and Inner Asia, such as the hunter-gatherers of Lake Baikal in Siberia, to a collection of naturally preserved mummies found in China’s Tarim Basin, dating to the Bronze Age, which lasted from about 2500 BC to 700 BC
While migration from North Asia to the Americas was thought to be largely unidirectional, the researchers found that ancestors related to Native Americans contributed about 50 percent to Iron Age Northeast Siberian DNA, whose gene flow likely occurred between 5500 and 5500 B.C.E. and 4,400 years ago. Genetic sharing has also been observed among the modern Koryaks, an indigenous group inhabiting the Kamchatka Peninsula, and is estimated to have occurred only 1,500 years ago.
Interestingly, some skeletal remains from the Russian Far East shared about a quarter of their genome with ancient humans dating back to Japan’s prehistoric Jomon period around 13,000 to 300 BC. This is probably not too surprising, since Japan shares a sea border with the Russian Far East.
Why is it important – The fact that some skeletal remains containing ancient genetic ancestors from Northeast Asia extended further west than what scientists had previously observed – about 1,500 kilometers – may suggest that the peoples of North Asia were strongly related as far back as 10,000 years ago.
“This suggests that human migration and admixture was the norm, not the exception, for ancient hunter-gatherer societies as well,” Posth said in a press release.