Genome complexity: new Tibetan altitude adaptations (Introduction)

by David Turell , Friday, May 23, 2025, 17:13 (10 hours, 0 minutes ago) @ David Turell

A study in women:

https://www.sciencealert.com/humans-are-evolving-right-in-front-of-our-eyes-on-the-tibe...

"'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."

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"To unlock this discovery, the researchers delved into one of the markers of what we call evolutionary fitness: reproductive success. Women who deliver live babies are those who pass on their traits to the next generation.

"The traits that maximize an individual's success in a given environment are most likely to be found in women who are able to survive the stresses of pregnancy and childbirth.

***

"Among the things they measured were levels of hemoglobin, the protein in red blood cells responsible for delivering oxygen to tissues. They also measured how much oxygen was being carried by the hemoglobin. Interestingly, the women who demonstrated the highest rate of live births had hemoglobin levels that were neither high nor low, but average for the testing group.

"But the oxygen saturation of the hemoglobin was high. Together, the results suggest that the adaptations are able to maximize oxygen delivery to cells and tissues without thickening the blood – a result that would place more stress on the heart as it struggles to pump a higher viscosity fluid more resistant to flow.

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"Taken all together, these traits increase the rate of oxygen transport and delivery, enabling the human body to make the most of the low oxygen in the air respired."

Comment: this article has a headline that touts evolution happening: "Humans Are Evolving Right in Front of Our Eyes on The Tibetan Plateau". Wrong! They are adapting to severe conditions. Homans have an enormous adaptive ability.