How one gene mutation helped indigenous Siberians to adapt to cold climate
Scientists have discovered genes that helped indigenous peoples of Siberia to adapt to life in a cold climate with a restricted diet. They found mutations in genes affecting lipid metabolism, a process that involves splitting, digesting, absorbing, transporting and accumulating fat in the body.
According to Ludmila Osipova from the Institute of Cytology and Genetics in Novosibirsk, this explains why indigenous Siberians have a low level of bad cholesterol despite eating fatty food like raw meat, fish and kidneys.
These genes are involved in the work of brown adipose tissue, which at the molecular level may be responsible for the low level of bad lipids in the blood. Brown fat activates when it is cold and releases energy to warm an organism. It requires fatty acids and glucose, which serve as a kind of “fuel”.
People with active brown adipose tissue have lower levels of bad cholesterol but higher levels of good cholesterol (high-density lipoprotein). If the cold lasts long enough, brown fat may require fuel all the time, continuously burning lipids.
Siberian natives have sped up metabolism and elevated levels of thyroxine, a thyroid hormone. Researchers believe discovered genes enable the mechanisms of the functioning of brown fat. First, thyroxin activates brown adipose tissue. Then, an increased release of energy leads to enhanced nutrition, which can cause rapid metabolism.
This adaptation mechanism becomes a risk factor when indigenous people switch to a lifestyle with a different type of food, including a large number of carbohydrates. As a result, a shift in metabolism occurs. It could lead to overweight problems, diabetes and hypertension. Scientists hope that further research will help find a solution to this problem.
Elia Kabanov is a science writer, covering the past, present and future of technology (@metkere)