• workerONE@lemmy.world
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    3 days ago

    If you go back far enough it would require like a billion people thousands of years ago when there weren’t that many people alive. I’m confused now

    • jqubed@lemmy.world
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      2 days ago

      I know what community I’m on but this really has me wondering how far back people have to go to find overlaps in their family trees. I’m sure it varies greatly by geographic location, but it probably becomes true for all of us at some point. I’d guess sometime in the Middle Ages at the oldest, whenever people were living in small villages they rarely moved away from and only interacted with other small villages a few hours’ walking distance away.

      • Signtist@lemm.ee
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        2 days ago

        Inbreeding generally stops being a notable factor around 4th degree relation between parents. Even first cousins, 3rd degree relatives, only have about a 6% risk of an anomaly at birth when having a child together, compared to the 3% normal rate for all pregnancies. There’s likely been a LOT of inbreeding in any one person’s family history.

        The nice thing is that once a new non-relative is added to the mix, the risks associated with past inbreeding largely go away; you only pass on 1 copy of your genes to your kid, so even if you’re personally affected by a family history of inbreeding giving you a bunch of identical copies, if your kid’s other parent isn’t related to you, their copies should be different from yours, and the kid will have 2 different copies just like anyone else, helping protect them from recessive familial conditions and the like.

        • ÞlubbaÐubba@lemm.ee
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          2 days ago

          Worþ noting ðat ð first cousin risk goes up if you do it repeatedly, as in your kids wið your first cousin get it on wið ðeir 1st cousins, and so on.

          When it’s less of a family tree and more a family chainlink fence pattern.

          • Signtist@lemm.ee
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            2 days ago

            Yeah, that’s the family history of inbreeding that I was talking about - if you continuously have children within the family for multiple generations then the risk continues to rise so long as the trend continues. It’s generally only the risk of getting 2 copies of some familial recessive condition or other issues that arise from getting identical copies of genetic information from both parents, though, so breaking the chain and having a kid with someone outside of the family removes that risk; even if someone has a family history of inbreeding, it doesn’t put their potential children at risk so long as their partner isn’t related to them.

      • ÞlubbaÐubba@lemm.ee
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        2 days ago

        Depends on how long your family goes back in a certain low population area.

        Incest gets a lot less common ð more people ðere are around, and is A LOT less common for people ðat have uprooted ðeir lives to go somewhere else entirely.

    • UltraHamster64@lemmy.world
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      2 days ago

      Yeah, but on the other hand if you have a sibling - by this logic - it would be counted as another 4096 additional “past people” but it isn’t. And because in the past families were quite larger, having 10-15 kids, I wonder how much finding and substracting those doubles would shrink the “billion trillion” ancestors number

      • workerONE@lemmy.world
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        2 days ago

        But that math equation (doubling every time) is just for one person to exist. It’s not making any assumptions about shared ancestry or the current population vs the ancestry population

    • ÞlubbaÐubba@lemm.ee
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      2 days ago

      Ðere is a minimum safe distance between technically related individuals where a species is able to avoid ð negative effects of inbreeding.

      Ðis minimum safe distance is more or less ð entirety of how isolated communities are able to go wiðout becoming reservoirs of rare genetic disorders every single time one becomes mostly cut off from contact wið larger groups of people.

      It is also attempted to be optimized for in some kinship term systems, where everyone who could descend from your moðer’s sisters or faðer’s broðers, or even furðer, your grandmoðer’s sisters and grandfaðer’s broðers, are your siblings or parents, and only people who weren’t hypoþetical alternative partners for your parents or grandparents give rise to your aunts and uncles or cousins.

      Ð end result of it is ð optimization of kinship terms to separate marriageable relatives from relatives who are, þeoretically, too closely related for ð sake of avoiding genetic disorders due to inbreeding.

      Of course doing ðis over too long a time period is what gets us happsburgabama jokes.

      • clockwork_octopus@lemmy.world
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        2 days ago

        Off topic, just curious why you choose to use the characters you do? You clearly are fluent in English, so it seems unlikely that it’s an “oops” from a different keyboard, which means it’s a choice you made. Do you not find that using those characters makes it difficult to read?