The movement of people through the mar de Bering, from North Asia to America, is a well-established and studied phenomenon in the history of human migrations. However, the genetic makeup of the populations that lived in North Asia around 10,000 years ago is poorly understood, and remains a mystery due to the limited number of ancient genomes from this region analyzed by scientists.
Now, a team of researchers led by Ke Wang, from Fudan University, in China, has described the genomes of ten individuals up to 7,500 years old, something that will help fill this gap and also shows how it produced the ‘gene flow’ of people moving in the opposite direction, that is, from North America to Asia.
The work has just been published in ‘Current Biology’.
In their analysis, the researchers reveal the presence of a previously undescribed group of early Holocene Siberian people who lived in the Altai-Sayan Neolithic region, near where Russia, China, Mongolia and Kazakhstan meet. Genetic data indicates that they were all descendants of Paleosiberian and ancient North Eurasian people.
an unknown population
“We describe a previously unknown 7,500-year-old hunter-gatherer population in Altai,” explains Cosimo Posth, from the University of Tübingen in Germany and senior author of the research, “which is a mix between two distinct groups that lived in Siberia during the last Ice Age. The Altai hunter-gatherer group contributed to many contemporary and later populations in North Asia, demonstrating how highly mobile those communities were.”
The Altai region is well known as the site where an entirely new group of archaic hominids, the Denisovans, was discovered years ago. But Altai is also important for human history, since for millennia it was an obligatory point of passage in the movements of populations between northern Siberia, Central Asia and East Asia. An authentic ‘meeting point’ for very diverse populations from a good part of the northern hemisphere.
In their paper, Posth and colleagues explain that the unique gene pool discovered by them may represent an optimal source for ancient North Eurasian populations that contributed to Bronze Age groups in North and Inner Asia, such as the hunter-gatherers of Lake Baikal or the associated herdsmen of Okunevo and Tarim. The team also discovered Ancient Northeast Asian ancestry, which was initially attributed to Neolithic hunter-gatherers from the Russian Far East and actually stems from another Altai-Sayan Neolithic individual.
The findings also reveal how the spread of Ancient Northeast Asian ancestry occurred up to about 1,500 km further west than previously observed. In the Russian Far East, they also identified 7,000-year-old individuals with associated Jomon ancestry, indicating links to hunter-gatherer groups in the Japanese archipelago.
From America to Asia
The data are also consistent with multiple phases of gene flow from North America to Northeast Asia over the last 5,000 years, reaching the Kamchatka Peninsula and central Siberia. The researchers note that the findings highlight a largely interconnected population across North Asia from the early Holocene onward.
“The finding that surprised me the most,” says Ke Wang, “is that of an individual dating from a similar period to that of the other Altai hunter-gatherers, but with a completely different genetic profile, as it shows affinities with populations located in the Russian Far East. Interestingly, the individual from Nizhnetytkesken was found in a cave containing rich grave goods, wearing a religious costume and objects interpreted as a possible representation of shamanism.
A multicultural region
For Wang, the finding implies that people with very different profiles and backgrounds were living in the same region at almost the same time. “It is not clear -says the researcher- if the individual from Nizhnetytkesken came from afar or if the population from which it came was located nearby. However, the grave goods from him appear different from other local archaeological contexts, implying the mobility of culturally and genetically diverse individuals in the Altai region.”
Taken together, the genetic data from Altai show that North Asia harbored highly connected groups from 10,000 years ago and over great geographical distances. “Which suggests – concludes Posth – that human migrations and mixtures were the norm and not the exception also for ancient hunter-gatherer societies.”