Produced by: Mohsin Shaikh
Humans on the Tibetan Plateau have adapted to thrive at high altitudes, where most would struggle. Over 10,000 years, their bodies have evolved traits that maximize oxygen delivery, a necessity for survival in these harsh environments.
High altitudes, like the Tibetan Plateau, cause hypoxia due to low oxygen levels. While mountain climbers suffer, Tibetan communities thrive, evolving in ways that allow them to overcome the oxygen deficit.
Researchers discovered that reproductive success plays a key role in human adaptation. Women who can survive pregnancy in these hypoxic conditions pass on traits that increase oxygen delivery, boosting their offspring’s survival rates.
Women with the highest birth rates had hemoglobin levels that were neither too high nor too low, but perfectly balanced. This adaptation allows for efficient oxygen delivery without stressing the heart, a crucial survival trait.
Anthropologist Cynthia Beall, who led the study, explains, "Understanding how populations like these adapt gives us a better grasp of the processes of human evolution." The study was published in the Proceedings of the National Academy of Sciences.
Credit: Reuters
The women with the most reproductive success also had unique heart traits—wider left ventricles that pump oxygenated blood more efficiently. This adaptation ensures maximum oxygen transport in a low-oxygen environment.
Credit: Reuters
Beyond biology, cultural factors play a role. Women who marry young and have long marriages tend to have more children, increasing their exposure to pregnancy, but the physiological traits still significantly influence reproductive success.
Credit: Reuters
Even women with lower oxygen transport traits had high reproductive success if they possessed other beneficial traits, showing the complex interplay of genetic and environmental factors in human evolution.
This study shows that natural selection is still shaping human physiology. The adaptations of the Tibetan Plateau people offer a fascinating glimpse into how we continue to evolve in response to environmental pressures.