A study of people living in the high altitudes of Tibet and Ethiopia points to convergent evolution, says anthropologist Cynthia Beall. Convergent evolution is when two separate populations change biologically in a similar way to adapt to a similar environment, yet use different mechanisms. (Credit: Andy Stoll/Flickr)

HEALTH & MEDICINE – Posted by Chris Sheridan-Case Western on Monday, January 7, 2013 11:15

How to thrive in thin air: It’s in the genes

CASE WESTERN (US) — Highlanders in Tibet and Ethiopia are both able to flourish in the low oxygen of high altitudes, but the ability to pass on the trait appears to be linked to different genes.

The adaptation is the ability to maintain a relatively low (for high altitudes) level of hemoglobin, the oxygen-carrying protein in red blood cells, at notably high altitudes. Members of ethnic populations who historically live at low altitudes naturally respond to the thin air by increasing hemoglobin levels. The response can help draw oxygen into the body, but increases blood viscosity and the risks for thrombosis, stroke, and difficulties with pregnancies.

Published in the journal PLoS Genetics, the research may also provide insight for managing high-altitude sickness and for treating low blood-oxygen conditions such as asthma, sleep apnea, and heart problems by revealing how populations can live in severe environments.

The duration needed to develop this physiological adaptation remains unclear. Researchers found the adaptation in an ethnic group that has lived high in the mountains of Ethiopia for at least 5,000 years, but not in a group that has lived high in the mountains for 500 years.

Read more: Futurity – How to thrive in thin air: It’s in the genes.

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