Scientists have discovered mutations in the genes of the inhabitants of Tibet and the Andes Mountains, which allow them to live at extreme altitudes.
These peoples live in different parts of the world and have many differences, but what they have in common is that mutations of one gene help them breathe at an altitude of more than 4,000 meters.
This is stated in a study published in the journal Science Advances, writes Science.
Tibetans in the Himalayas have a mutation in the gene EPAS1, which helps to survive in conditions of lack of oxygen. An “Andean” variant of the same gene helped the Quechua population in the Andes to adapt to life at extreme altitude.
Both groups independently developed similar adaptations to survive in the highlands.
Scientists say that this is a vivid example convergent evolution – the formation of similar signs in representatives of unrelated groups.
|A representative of the Quechua people. Photo: VisualCommunications/GettyImages
Why do some peoples breathe easier in the mountains?
Most people can live comfortably at or slightly above sea level. But already at an altitude of more than 2.5 thousand meters above sea level, they develop altitude or “mountain” sickness.
People suffering from altitude sickness may experience nausea, confusion, and swelling of the lungs and brain. The higher the ascent, the stronger the symptoms of oxygen starvation.
Many climbers die in the mountains precisely because of a lack of oxygen: and not only at an altitude of 8,000 meters or more.
However, some peoples find it easier to climb the highlands than others. Let’s even mention the indigenous people of Nepal (Sherpas), who accompany tourists to Everest.
Scientists have long been trying to find out why some peoples constantly live at altitude and at the same time do not experience symptoms of altitude sickness. Among them are the Peruvian people Quechuawhich has been living high in the Andes for over 10,000 years, and Tibetan natives, who also feel comfortable at an altitude of over 4,000 meters. What do they have in common?
According to scientists, the inhabitants of Tibet and the Andean group have common physiological features (for example, larger lungs). But the basic mechanisms that help them cope with high-altitude life are different.
For example, thanks to some evolutionary processes, Tibetans are better at gaining body weight. At the same time, the inhabitants of the Andes have gene variations associated with better development of the heart muscle.
The researchers also suggest that growing up in the harsh conditions of the Andes causes epigenetic changes that do not affect the DNA sequence itself.
Another important difference between these groups is that some the inhabitants of the Andes have an extremely high level of hemoglobin in their bloodwhich allows you to get the necessary oxygen.
At the same time, the concentration of hemoglobin in Tibetans is below average, but it is enough for them.
In 2010, a team of researchers discovered that the EPAS1 gene and its mutations allow Tibetan mountaineers to use hemoglobin as efficiently as possible and receive more oxygen.
Now, the same scientists, under the guidance of geneticist Tatum Simonson from the University of California, studied the genomes of 40 representatives of the Quechua ethnic group living in the Andes, or more precisely, in a Peruvian town at an altitude of more than 4,000 meters.
The analysis showed that the inhabitants of the Andes also have a version of the EPAS1 gene that allows them to receive more oxygen even with low hemoglobin levels.
“I was surprised to see that EPAS1 was involved.”– comments geneticist Emilia Huerta-Sanchez from Brown University, who was not involved in the new study.
Huerta-Sanchez discovered 10 years ago that the inhabitants of Tibet inherited their unique variant of the EPAS1 gene from the “Denysov Man” – an ancient subspecies that died out about 40,000 years ago.
However, the mutation present in modern Quechua arose about 20,000 years after that. It was at that time that people first began to live in the Andes.
Scientists hope that their research in the future will help the inhabitants of the Andes, who still have problems with living at high altitude. After all, even in the Quechua population, not everyone tolerates altitude equally well.
It will be recalled that earlier scientists discovered a gene that forms the risk of a heart attack.
Read also: Genes that helped humanity survive the plague affect us today – study