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Re: [evol-psych] Incest and basic genetics

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  • Mike Waller
    Please generally feel free to hit me over the head with a very large stick, but entirely fail to se the need to introduce any complexity into this. It is true
    Message 1 of 4 , Feb 1, 2001
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      Please generally feel free to hit me over the head with a very large stick,
      but entirely fail to se the need to introduce any complexity into this. It
      is true that heavy inbreeding is a highly effective way of breeding out
      deleterious recessives by the simple expedient of eliminating any progeny in
      which they are express. These is what stockbreeders do with great success.
      However, the risk with this in the natural world is directly comparable with
      what engineers call a type-fault i.e. a defect in the basic design that
      means all representatives will suffer from it. With manufactured items, some
      designs can be so good that, in the short run, no type faults appear.
      Unfortunately nothing is forever, so the emergence of an even better
      retro-introduces what amounts to a type fault into what had previously
      seemed a near perfect design. The speed with which this happens is a
      function of the volatility of the market. So in really volatile markets the
      presumption is no long runs. Just: keeping ahead of the competition means
      change, change, and change again. The fashion industry seems to be a case in
      point.

      My simple mind says the same range of volatility exists in nature. Some
      species occupy such nice stable niches that they don't even need sexual
      selection. Of course, if there is, say, a major climatic change, they can be
      completely screwed. On the other end of the scale, are species which need
      continually to be seeking variety to say ahead of competitors (conspecifics
      and otherwise) and to avoid parasites which very much favour standard models
      as these enable them to simplify their parasitic strategy. Ergo, or so it
      seems to me, if the long term "strategy" of a given type of vehicles is to
      get better and better at doing exactly the same thing, including fighting
      off exactly the same predators and diseases, there is not going to be room
      for an anti-incest gene to earn an honest living. If the reverse applies,
      there will be. In terms of nutshell advice to a human female: if you are
      convinced that your father has all the answers to everything for all time,
      sleep with your bother. If not, chose the smartest lodger. Reconverting this
      advice to the only thing which (to me!!!!) makes evolutionary sense, "Carry
      an anti-incest gene". This then is the all-in-evolutionary-all of incest
      avoidance: a smart strategy in appropriate conditions for the perpetuation
      of ant-incest genes!!!! Why make it anymore complicated?

      Mike
    • Alex RB
      You are using the term sexual selection with a meaning that is different than the meaning every one else would use. Sexual selection is a modality of
      Message 2 of 4 , Feb 1, 2001
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        You are using the term "sexual selection" with a meaning that is different
        than the meaning every one else would use. Sexual selection is a modality of
        selection that happens within the context of mating, and includes, but is
        not restricted to, pre-mating rituals, competition for mates, sperm
        competition, female cryptic choice, post-mating selection etc. It is true
        that some species occupy more stable environments and that variation is not
        crucial for them, in principle. On the other hand, asexually-reproducing
        organisms do not usually occupy stable environments, but they have ways to
        compensate for it. Eventual inbreeding is not a problem for our species but
        may be for the individuals involved, if they carry nasty recessives. If
        there is any genetic determination for incest avoidance, it is not that
        strong, because incest is known to occur in several instances, and its
        avoidance is STRONGLY reinforced by culture, for reasons that go beyond
        avoidance of inbreeding depression.

        >
        > My simple mind says the same range of volatility exists in nature. Some
        > species occupy such nice stable niches that they don't even need sexual
        > selection. Of course, if there is, say, a major climatic change, they can be
        > completely screwed. On the other end of the scale, are species which need
        > continually to be seeking variety to say ahead of competitors (conspecifics
        > and otherwise) and to avoid parasites which very much favour standard models
        > as these enable them to simplify their parasitic strategy. Ergo, or so it
        > seems to me, if the long term "strategy" of a given type of vehicles is to
        > get better and better at doing exactly the same thing, including fighting
        > off exactly the same predators and diseases, there is not going to be room
        > for an anti-incest gene to earn an honest living. If the reverse applies,
        > there will be. In terms of nutshell advice to a human female: if you are
        > convinced that your father has all the answers to everything for all time,
        > sleep with your bother. If not, chose the smartest lodger. Reconverting this
        > advice to the only thing which (to me!!!!) makes evolutionary sense, "Carry
        > an anti-incest gene". This then is the all-in-evolutionary-all of incest
        > avoidance: a smart strategy in appropriate conditions for the perpetuation
        > of ant-incest genes!!!! Why make it anymore complicated?
        >
        > Mike
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