Thursday, November 22, 2018

Cool Science

For over 1,000 years, the Bajau people have lived on boats around Indonesia. They spend the majority of their time hunting underwater for food and coral. Scientists wondered if generations of oxygen deprivation had tweaked their genes.

This was not so far-fetched. High-altitude populations in Tibet, South America, and Ethiopia have genetically adapted to live with low oxygen levels. Even so, the researchers were skeptical about finding anything. A thousand years was short for evolution, and these people did not live at high altitudes.

The 2018 study quickly converted the weary when they measured 59 spleens from Bajau and 34 from a nearby village. The divers’ spleens were 50 percent bigger. When anyone dives, the spleen contracts to provide the body with oxygen-rich red blood cells.

DNA tests confirmed that the Bajau had 25 different genes and one of them, PDE10A, affects spleen size in mice. Despite misgivings from the scientific world, the study presents strong evidence of natural selection in living humans. In the case of the Bajau, it helps them to better “breathe” underwater by storing more oxygenated red blood cells inside their hefty spleens.

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