Tibetans evolved to live at an altitude of 4,000 m

Research published in the journal PNAS by Cynthia Beall, a professor at Case Western Reserve University, reveals the adaptive characteristics that help Tibetan women not only survive but also thrive in the harsh environment of high mountains. . Breathing thin air at high altitudes is a survival challenge but research results show that the unique physiological characteristics of Tibetan women have improved their fertility despite low oxygen levels in the mountains. surroundings, according to Sci Tech Daily.

Beall and his colleagues studied 417 Tibetan women between the ages of 46 and 86 living at an altitude of 3,657 – 4,267 m above sea level in Upper Mustang, Nepal at the southern edge of the Tibetan plateau. They collected data on the women’s reproductive history, took physiological measurements, took DNA samples and assessed social factors. They wanted to understand how the oxygen delivery characteristics of high-altitude hypoxia affect the number of births. This is a key measure of good evolutionary ability.

Researchers found that most children have a unique set of blood and heart characteristics that help the body transport oxygen. Women who gave birth to the most children had hemoglobin (oxygen transport molecule) levels, close to the sample average, but much higher oxygen saturation, allowing more efficient oxygen transport to cells without Does not increase blood viscosity.

“This is a case of natural selection at work. Tibetan women evolved in a way to balance the body’s need for oxygen without overloading the heart,” Beall commented.

Beall’s interdisciplinary research team, including Brian Hoit and Kingman Strohl at Case Western Reserve School of Medicine and many other international scientists, conducted fieldwork in 2019. They actively worked with local communities in the region Himalaya, part of Nepal, hires indigenous women as research assistants and collaborates with many population leaders.

One genetic trait they studied likely originated with Denisovans who lived in Siberia about 50,000 years ago. Descendants of the Denisovans later migrated to the Tibetan plateau. This trait is a variant of the EPAS1 gene found only in indigenous communities on the Tibetan plateau, which helps regulate hemoglobin levels. Other features such as increased blood flow to the lungs and wider ventricles also help enhance oxygen transport. These traits contribute to greater reproductive success, providing insights into how humans adapt to low oxygen levels in the air and body throughout life.