People, like animals living at high altitude, have learned to deal with difficult natural conditions. But the secret lies not only in lifestyle changes, but also in the ability of the Tibetans to evolve.
The biggest problem people face when living at high altitude is low air pressure. This complicates the flow of oxygen to the lungs, which is the cause of many problems. People have a high-altitude illness at altitudes greater than 8,000 feet (about 2438.4 m).
Symptoms of the disease: lack of appetite, headache, nausea and difficulty thinking and somnolence. In more severe cases, the liver can accumulate in the heart and the brain, bleeding may begin in the lungs and serious heart problems.
Some of the symptoms are more delicate. For example, it's so hard to get pregnant in the mountains. However, it is unlikely that the Tibetans are suffering from these problems, they are saved by gene mutations.
It has been estimated that around 8000 years ago, certain changes occurred in the EGLN1 gene. Today, up to 88% Tibetans have this altered gene that protects the organs from excessive reactions due to low oxygen content.
This Tibetan adaptation at high altitudes also related to a genome called EPAS1, which is involved in a low-oxygen reaction in the body.
Rasmus Nielsen and his colleagues at the University of California in 2014 discovered that no other group of contemporary people has the Tibetan EPAS1 gene.
Our red blood cells that carry oxygen are called hemoglobin. When people travel to high altitude, conventional EPAS1 variants cause too much hemoglobin, says Nielsen. It causes blood thinning, heart attacks, reduces the weight of children and increases child mortality.
However, the Tibetan variant of the gene prevents this path. He high hemoglobin and red blood cells raise only slightly, avoiding the side effects that many people find, says Nielsen.
The same changes in the animal's blood were also detected. For example, Tibetan Mastiff dogs live near high Tibetans, and by 2014 their DNA was discovered as an exclusive version of the EPAS1 gene.
When animals are raised, they are extraordinarily endurable. Many of them are real highway recorders.
More :
Living on the "roof of the world". Part One: A Diversity of Life
Living on the "roof of the world". Part Two: Walking At a Height Of 4 km
