Northern genes
Geneticists have revealed the secrets of survival of Yakuts and Nganasans
Geneticists from Russia and the United States have deciphered the DNA of Yakuts and Nganasans and discovered unusual versions of genes that allow these peoples of the North to survive in conditions of constant cold, polar night and a diet consisting almost entirely of meat and fats, according to an article published in the journal Molecular Biology and Evolution.
"The analysis of our data helped us to identify seven genes associated with life in the north of Siberia. Three of them are related to diet, especially fat metabolism, which suggests that the Yakuts, Nganasans and other peoples of the north have adapted to a diet rich in animal fats. In addition, they all play an important role in energy production, in protein metabolism and in the work of cell membranes," says Ryan Gutenkunst from the University of Arizona (in a press release Cold comfort: Fat—rich diets and adaptation among indigenous Siberian populations – VM).
Eskimos, Chukchi and many other northern nationalities, as well as the inhabitants of Tibet, are of great interest to geneticists, as they have adapted to life in extreme conditions, where people from more southern countries usually do not survive. For example, genetic studies of Tibetans helped scientists to identify the genes that the inhabitants of this highlands inherited from the ancient people-"Denisovites" and which helped them adapt to the lack of oxygen in the mountains.
The problem, as Gutenkunst says, is that the "pure" populations of representatives of these northern and mountainous peoples have almost completely disappeared today, which prevents the search for such DNA sites and the study of how they could help their ancestors survive in the harsh conditions of the mountains and the north. For example, at the moment in Less than a thousand Nganasans and about 480 thousand Yakuts live in Russia.
To solve this problem, Gutenkunst and his colleagues joined forces with the Russian Institute of Cytology and Genetics SB RAS in Novosibirsk, whose specialists helped American geneticists obtain DNA samples of Yakuts and Ngasans, decipher and analyze them. In total, scientists analyzed over 500 thousand "point" mutations in their DNA in an attempt to find "Siberian" genes.
This analysis, according to scientists, indicated that the Yakuts and Nganasans, despite the cardinal differences in lifestyle – the former are nomadic pastoralists, the latter are hunter-gatherers – are close relatives. Their ancestors separated about 13 thousand years ago, and subsequently they had almost no contact with each other.
This date, according to scientists, was not accidental – at this time the glaciers began to retreat for the last time, which allowed the peoples of the Far North to expand their habitats and begin to live in territories freed from ice. Both Yakuts and Nganasans subsequently experienced sharp reductions in numbers, which indicates the extremely harsh conditions in Siberia at that time and a difficult history of adaptation to them.
This "struggle with nature", as scientists note, has led to the emergence of a whole set of genes that allow Yakuts and Nganasans to eat almost exclusively a meat and fatty diet and not experience serious health problems. The presence of these mutations in their DNA, according to scientists, suggests that both peoples were originally hunter-gatherers, and only then the Yakuts were able to tame deer, breed northern cows and become nomadic pastoralists.
These mutations, which help Yakuts and Nganasans to maintain low cholesterol and fat levels in their blood and not die from hypothermia, can help scientists uncover the roots of diseases associated with the disruption of these genes, and create new ways to protect the body from such problems.
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13.09.2017