Slashdot Mirror

← Back to Stories (view on slashdot.org)

'Sea Nomads' Are First Known Humans Genetically Adapted To Diving (nationalgeographic.com)

Posted by BeauHD on from the years-in-the-making dept.

schwit1 shares a report from National Geographic: Most people can hold their breath underwater for a few seconds, some for a few minutes. But a group of people called the Bajau takes free diving to the extreme, staying underwater for as long as 13 minutes at depths of around 200 feet. These nomadic people live in waters winding through the Philippines, Malaysia, and Indonesia, where they dive to hunt for fish or search for natural elements that can be used in crafts. Now, a study in the journal Cell offers the first clues that a DNA mutation for larger spleens gives the Bajau a genetic advantage for life in the deep.

6 of 111 comments (clear)

  1. Why the spleen matters by JoshuaZ · · Score: 5, Informative

    From TFA: When you go hold your breath and are surrounded by water you have a bunch of physiological responses that happen automatically. One major one is that your spleen contracts delivering more red blood cells to your arteries. Since they have larger spleens, there's a larger reservoir of red blood cells ready to get pushed out when necessary.

    1. Re:Why the spleen matters by skids · · Score: 4, Funny

      I was about to say "I must have a really small spleen these days considering how much I hate holding my breath."

      But I guess that reasoning is void, because I haven't been fully immersed in water in decades... so...

      --
      Someone had to do it.
  2. Re:Evolution Continues by ShanghaiBill · · Score: 4, Insightful

    Maybe after a few thousands years of living in space in the future, our species evolves the mutations necessary to combat the ill effects of micro gravity and radiation.

    I don't think so. Genetic engineering is making rapid progress. Future changes to humanity will be by design, not through random mutations.

  3. Re:Germans by Jodka · · Score: 4, Insightful

    The world record holder for underwater breath-holding is German.

    Maybe the Bajau are under-represented entrants in the contest.

    --
    Ceci n'est pas une signature.
  4. Re:Are we sure it’s genetic by quenda · · Score: 3, Insightful

    and not heavy training from a young age?

    RTF Study summary:

    Using a comparative genomic study, we show that natural selection on genetic variants in the PDE10A gene have increased spleen size in the Bajau, providing them with a larger reservoir of oxygenated red blood cells. We also find evidence of strong selection specific to the Bajau on BDKRB2, a gene affecting the human diving reflex.

    So yes, there is a genetic basis for part of the different abilities between races, and we are starting to find it.
    I wonder if National Geographic will one day be apologising for how racist they were to print this?

    https://www.nationalgeographic...

  5. Re:Germans by Anonymous Coward · · Score: 4, Informative

    Hyperventilating is dangerous and is specifically advised against during freediving courses. The reason is twofold.

    First, our urge to breathe is controlled by high CO2, not low O2, and hyperventilation removes CO2 from the blood without adding much O2 (it's already at 97+% of the possible maximum by default). Three deep breaths is the golden middle that fully replaces CO2 with O2 in lungs without affecting the blood composition too much. So those who hyperventilate do not, actually, get more time until a blackout, they just get "more comfortable" time, and "more comfortable" to a not really predictable degree. I.e. useless to really say "enough" to oneself.

    Second, red blood cells are not willing to give away the oxygen they are carrying if there is not enough CO2.