Why The Tibetan Plateau Holds The Key To A New Era Of Human Evolution

A new study has found that for the past 10,000 years, populations on the Tibetan Plateau have developed particular adaptations to survive in the low-oxygen conditions surrounding the region. While most people would succumb to hypoxia - a condition in which the body is unable to get enough oxygen - the Tibetan communities have thrived despite the thin air.

The study shows humans are still undergoing evolution in the sense that they adapt to such difficult living situations. In Tibet, for instance, where levels of oxygen exist much lower compared to sea levels, people act normally, though mountain climbers encounter altitude sickness due to the problem of low availability of oxygen levels.

While it would be hard to breathe in the region's thin air, generations of Tibetan people have adapted to the situation, making their bodies optimised to obtain as much oxygen as possible from the air. This helps them live more life in a place where others might merely manage to survive.

This phenomenon is clarified by the research conducted by Cynthia Beall, a University Professor Emerita at Case Western Reserve University. The study, which was published on October 21 in the Proceedings of the National Academy of Sciences (PNAS), shows how the physiological characteristics of Tibetan women enhance their capacity to procreate in an oxygen-poor environment.

"Adaptation to high-altitude hypoxia is fascinating because the stress is severe, experienced equally by everyone at a given altitude, and quantifiable," anthropologist Cynthia Beall of Case Western Reserve University in the US told ScienceAlert. "It is a beautiful example of how and why our species has so much biological variation."

When comparing the pregnancy-related biology of Tibetan women with that of migrants to high altitudes, Tibetan women have lower hemoglobin concentration, higher oxygen saturation of hemoglobin and uterine artery blood flow, and heavier newborns. Among Tibetan women who have completed childbearing, unelevated hemoglobin concentration, higher oxygen saturation, and a higher pulse rate correlate with higher lifetime reproductive success. This pattern of human variation suggests the action of natural selection on oxygen delivery phenotypes.

This research shows that human evolution is still an ongoing process, as our bodies continue to adapt to our surroundings. The Tibetan Plateau, which has been inhabited for over 10,000 years, presents a unique example of how humans evolve to survive in extreme environments.