• owenfromcanada@lemmy.ca
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    2 days ago

    No.

    People have lived into their 80s for millenia. Average lifespan used to be shorter because of the amount of infant mortality. That is, anyone who made it out of childhood was likely to make it at least to their 60s, barring things like war and plague.

    The simpler explanation is that the study is cookydooks.

    • Buffalox@lemmy.world
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      2 days ago

      Average lifespan used to be shorter because of the amount of infant mortality.

      That is completely wrong.
      Lifespan is NOT the same as life expectancy:

      https://my.clevelandclinic.org/health/articles/lifespan

      Lifespan is the maximum length of time that a person can live

      https://www.discovermagazine.com/what-was-the-life-expectancy-of-ancient-humans-44847

      Other research reveals that the lifespan of Homo sapiens may have changed from the Middle Paleolithic to the later Upper Paleolithic, since the ratio of older to younger remains increases. The same research shows that starting about 30,000 years ago at the beginning of the Upper Paleolithic, the average lifespan began to push past 30 years.

      So 30000 years ago 30 years was pretty much the maximum age a person could achieve. Life expectancy would probably have been more around 15.

      Read my other comment, the study is probably pretty close to the truth.
      https://lemmy.world/comment/19682894

    • Talonflame (she/her)@lemmy.cafeOP
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      2 days ago

      According to the article it’s not about life expectancy, but that the lifespan of 38 is hardcoded into our DNA/Telomeres

      • AbouBenAdhem@lemmy.world
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        2 days ago

        Unless I missed something, the word “telomere” doesn’t occur in the article or its source paper—rather, it discusses the rate of DNA methylation.

        IMO, the key passage in the paper is this:

        However, any genetic regulation for a species may potentially be a secondary factor as there may be other environmental selective pressures. This may be the case with species which have lifespans post reproductive age and therefore, there may be non-genetic factors that may be more predictive of their maximum lifespan.

        I suspect that the methylation rate is actually tracking the end of the reproductive stage of the lifecycle, rather than the entire lifespan—it’s just that humans have an unusually long post-reproductive stage.

        • Talonflame (she/her)@lemmy.cafeOP
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          1 day ago

          It’s saying 38 is the maximum lifespan of a human, determined by genetics, and the only reason we can live past 38 is due to unnatural interventions ie medicine

          • AbouBenAdhem@lemmy.world
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            1 day ago

            It’s saying 38 is the maximum lifespan predicted by their model—but it also says their model has an R2 of 0.76, meaning it only predicts about 76% of the variation in the actual measured values. And then they discuss other factors that could account for the remaining 24% of the variation, including post-reproductive-age lifespan.

      • owenfromcanada@lemmy.ca
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        2 days ago

        I’m not sure what the difference between “lifespan” and “expectancy” is other than semantics, given the context of your questions. Regardless of what our DNA says, our life expectancy is typically in the 70s or 80s, and that hasn’t changed much throughout known human history, so it has nothing to do with modern technology.