4 ms·

Thank you for the insight. I wonder, how do we know the males were infertile?

• danieltillett 11y ago
  We don't - all we know is that the Neanderthal Y chromosome is missing from the modern human population. This could have occurred by chance (genetic drift), lethal genetic incompatibility (all males died), or infertility. Given the data we have it is hard to know which of these is the real cause.
  • thedevil 11y ago
    Is it not equally likely the other way around - that the Neanderthal mitochondria disappeared because of unsuccessful mixed females or other genetic drift?
    • klipt 11y ago
      Yeah, given the symmetrical evidence: no Neanderthal Y chromosome DNA, and no Neanderthal mitochondrial DNA - it seems most gendered hypotheses you could come up with should also work with the genders switched?
    • danieltillett 11y ago
      No because of the way genetics works it is much more likely to be the Y chromosome that is lost. First the Y chromosome is under stronger indirect selection than the mitochondria due to asymmetric mating. Second in mammals when two different species have a genetic incompatibility this incompatibility manifests in the male offspring. Both of theses point towards male Neanderthal female African as the way this hybridization happened. Edit. I should add the scientific paper behind this New Scientist article proposes a precise genetic mechanism for how the Neanderthal Y chromosome is lost which is further evidence the loss is due Y Chromosome incompatibility.