Genetic adaptations to diving discovered in humans for the first time

Discussion in 'Human Science' started by CEngelbrecht, Apr 21, 2018.

  1. CEngelbrecht Registered Senior Member

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    Eh? The Bajau is a whole population, too. There's a million of them, the Inuit is about 150,000, the Sherpas about 275,000.

    https://en.wikipedia.org/wiki/Sama-Bajau
    https://en.wikipedia.org/wiki/Inuit
    https://en.wikipedia.org/wiki/Sherpa_people
     
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  3. Bells Staff Member

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    Yes. But they are spread out.

    The ones cited in this study are in Indonesia. Hence why I questioned earlier, if the population around Asia bore the same enlarged spleen.
     
    Last edited: Apr 23, 2018
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  5. CEngelbrecht Registered Senior Member

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    What, more than the Inuit?

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    So-called "Sea Nomads" - Blue: Moken | Orange: Orang Laut | Green: Sama-Bajau

    In the paper, their spleen size is compared directly with their landlocked neighbours on Sulawesi. That's the summary of the study: Their continuous aquatic lifestyle is what has given them such genetic adaptations as coding for larger spleens, enabling longer breathhold diving.

    http://www.cell.com/cell/fulltext/S0092-8674(18)30386-6
     
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  7. Bells Staff Member

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    Judging by their spread throughout Asia, possibly yes.

    Who aren't of the same tribe. They are close, live similar types of lives, but it seems they aren't that close.. The bit about the Denisovans in the study that you linked was very interesting.

    Well they would need to test other groups who live in a similar fashion (ie sea nomads) as this could be occurring in other populations as well.

    They also need to see if this is occurring in other Bajau populations across Asia as well. You know, before they can make such a definitive declaration.
     
  8. CEngelbrecht Registered Senior Member

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    Looking at those two maps above, are the Bajau suddenly more spread out on the planet than the Inuit?

    Researchers have been very definite about things on much less evidence than that. Big Bang theory springs to mind.

    Diving for food gives people a larger spleen to increase their breath hold. Makes all the sense in the world. What is the problem?
     
  9. iceaura Valued Senior Member

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    Exactly the kind of situation that would come up, once in a while, in people whose lives depended on that kind of foraging.
    That is - sometimes - not going to be an option, when feeding families (or oneself, as a child).

    At which time the cull is likely to take the children with the smaller spleens who get sick from diving more easily, the progeny of the adults who can't push themselves as far, first.

    There's (I have, anyway, and think I observe not necessarily here but in general) an inevitable perception bias toward seeing amphibious foraging as an easy life, because in normal circumstances (nine times in ten when the observer observes) it is. Nobody's working too hard, there's plenty of slack. That's partly because it varies a lot, over time and space - and the bad times or the marginal areas of an expanding population (or, in the case of humans, wisdom-imitating cultural adaptations normally involving spiritual authority, sexual preferences, narrative tradition, etc) keep the population at a level the normal times support with minimal effort. Selection events happen.
    - - - -
    They can. Also, an initial selective advantage can "create" cultural practices. These diving cultures came from somewhere, and if the founding population had an advantage in diving ability over their erstwhile neighbors that would not be too surprising - with the cultural practices, the tricks of the trade, building later.

    Combine that with the Baldwin Effect and the other selection above, and very rapid genetic change is possible.
     
  10. CEngelbrecht Registered Senior Member

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    Right, fair enough, it is a possibility, but these incidents of bends in spearfishers are extremely rare.

    Well, I mean, fishing freedivers like in the BBC clip above don't venture to 300 feet to hunt for food, that's primarily competitive freedivers. Simple hypoxic drowning would be a much more common selective factor under such conditions. Or though I also think the ones simply gathering the most food would be a dominant factor in ensuring the survival of their offspring and therefore selection.
     
  11. Bells Staff Member

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    There are Bajau communities in several countries across Asia. Why are you attempting to dispute this?

    The current study, while extraordinary, focused on a group in one part of Indonesia. There are other Bajau communities elsewhere in Indonesia, Malaysia, Thailand, Vietnam, etc. And it would be interesting to study them as well to see if they also have enlarged spleens, or to see if this is just something that has occurred in this one group in Indonesia.

    And?

    Just because this has occurred with one group, does not mean that the same adaptations exist in other Bajau groups. Hence why this needs to be looked at further.

    And there is plenty of evidence for the Big Bang. But there is no evidence that this adaptation exists with other groups. Understand now?

    There is no problem. But just because this exists within one group, does not mean that the Bajau people across Asia have the same adaptation, just as it does not mean that other communities that dive for their food will either.

    To begin with, it would be interesting to see if all Bajau people carry the same gene results in their thyroids producing more hormones, which resulted in the enlarged spleens. Or if this is something that occurred locally.

    It's still early days yet.
     
  12. exchemist Valued Senior Member

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    Sure.
     
  13. CEngelbrecht Registered Senior Member

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    They did. (Danish link

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    https://videnskab.dk/krop-sundhed/e...havfolk-i-sydoestasien-er-blevet-superdykkere
    "Not least, it was fascinating, that Bajau individuals who had abandoned the diving lifestyle also had enlarged spleens.
    It illustrated, that it was not the actual diving activity that had enlargened the spleen, but something else, that was likely genetic."
    "Ikke mindst var det spændende, at bajau-individer, som havde forladt livsstilen med at dykke, også havde forstørret milt.
    Det vidnede om, at det ikke var selve dykke-aktiviteten, som havde gjort milten større, men noget andet, som sandsynligvis var genetisk."

    This is solid.

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  14. CEngelbrecht Registered Senior Member

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  15. Bells Staff Member

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    Yes. But you are still missing the obvious point.

    It is still within the group in that part of Indonesia. There is nothing about the other groups and communities around Asia. Do you understand now?
     
  16. CEngelbrecht Registered Senior Member

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    No. I do not.
     
  17. Beaconator Registered Senior Member

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    Google muff diving...
     
  18. CEngelbrecht Registered Senior Member

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    Is that the level we're at?


    Yeah, I know. Who gives a F about science?
     
  19. exchemist Valued Senior Member

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    Er that procedure does not in itself lead to more children.
     
  20. Beaconator Registered Senior Member

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    It does if your a ballchinian...
     
  21. CEngelbrecht Registered Senior Member

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    I guess there is nothing to challenge about this find, when people resort to divert using really bad, unfunny innuendo.
     

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