A recent study has uncovered evidence of natural selection among Tibetan women living in high-altitude regions of Nepal. Published on October 21 in the journal PNAS, the research indicates that women with physiological traits suited for low-oxygen environments are more likely to have higher reproductive success.
The study analyzed over 400 women aged 46 to 86 in the Upper Mustang District, situated between 11,500 and 13,500 feet (3,500 to 4,100 meters) above sea level. These women face challenges such as hypoxia, which can lead to severe health issues during pregnancy.
Researchers found that women who bore more children exhibited specific physiological traits, including higher blood flow to the lungs and wider left ventricles in the heart, enabling better oxygen delivery. Notably, around 80% of the participants carried a variant of the EPAS1 gene, which is thought to help regulate hemoglobin levels, reducing the risk of chronic mountain sickness.
These findings contribute to our understanding of human evolution and may have implications for medical research related to low-oxygen conditions, such as asthma.