• sylver_dragon@lemmy.world
    cake
    link
    fedilink
    English
    arrow-up
    19
    ·
    1 day ago

    The thing about inbreeding is that it isn’t an instantly bad problem. The Habsburg dynasty was all about doing the nasty with cousins for a number of generations. It took a few rounds before the Habsburg Chin developed. Records also indicate that sister marriage was a common royal practice in pharonic Egypt.

    It’s all a matter of probabilities and compounding problems. The first generation of inbred kids will probably turn out ok. With the second generation things can start getting sketchy. The more generations you go, the more likely you are to get Crimson Tide fans.

    This is also why populations under a certain size can be problematic. When the family trees of a population start looking like brambles, problems start sticking out like thorns.

    • AbouBenAdhem@lemmy.world
      link
      fedilink
      English
      arrow-up
      3
      ·
      1 day ago

      It gets worse over time but it also eventually gets better, after the deleterious recessive alleles have been eliminated. Like in herd animals where a herd has only one breeding male per generation, so every generation is half-siblings.

      The general rule is that a population with a fixed degree of inbreeding will have a corresponding number of deleterious alleles so that the selection pressure balances out; but when you change the degree of inbreeding, you get a spike in expressed mutations until things balance out again.

      • HobbitFoot @thelemmy.club
        link
        fedilink
        English
        arrow-up
        2
        ·
        1 day ago

        Not necessarily. If the problem is on a recessive gene or it isn’t a problem with only one out of two genes expressing the trait, the genetic disease won’t get bred out of the family.