That is only if all deleterious alleles are recessive. Though of course, we don’t have any numbers and can imagine anything.
ETA: and a single recessive deleterious allele in the father’s genome would have disproportionate consequences. Although there would be about 50% chance of getting it, humans carry lots of such stuff, so overall probability of weak (but at least viable) progeny should still be high enough.
Inbreeding just makes it more likely you get two of the same allele (with bad consequences if said allele is deleterious), it does not make it inherently more likely that any single allele you have is deleterious.
True. And a progressively large portion of progeny would die before procreating, exactly because of that. Maybe there would even be bottlenecks along the way.
Yet it seems to me that a squib (?) whom Merope chose could have a different set of heterozygous=hidden deleterious alleles, which in Merope’s genome would not have been eliminated yet, but getting close to it.
Also, how on Earth was Slytherin’s curse even inherited? It would be something outside of genes, since he didn’t know about their existence. So the ability would be develop undiminished with blood ‘dilution’, which means a Parselmouth cannot be seen as evidence of pure-bloodedness, which would be a blow to Draco’s belief in his father’s ethics… And in Harry’s belief in genes-only inheritance...
Now, if Salazar was secretly a woman, and only daughters would get to be Parselmouths, that would be another story...
That is only if all deleterious alleles are recessive. Though of course, we don’t have any numbers and can imagine anything.
ETA: and a single recessive deleterious allele in the father’s genome would have disproportionate consequences. Although there would be about 50% chance of getting it, humans carry lots of such stuff, so overall probability of weak (but at least viable) progeny should still be high enough.
Inbreeding just makes it more likely you get two of the same allele (with bad consequences if said allele is deleterious), it does not make it inherently more likely that any single allele you have is deleterious.
True. And a progressively large portion of progeny would die before procreating, exactly because of that. Maybe there would even be bottlenecks along the way.
Yet it seems to me that a squib (?) whom Merope chose could have a different set of heterozygous=hidden deleterious alleles, which in Merope’s genome would not have been eliminated yet, but getting close to it.
Also, how on Earth was Slytherin’s curse even inherited? It would be something outside of genes, since he didn’t know about their existence. So the ability would be develop undiminished with blood ‘dilution’, which means a Parselmouth cannot be seen as evidence of pure-bloodedness, which would be a blow to Draco’s belief in his father’s ethics… And in Harry’s belief in genes-only inheritance...
Now, if Salazar was secretly a woman, and only daughters would get to be Parselmouths, that would be another story...