These don’t seem to be related to anencephaly in particular? Not sure if you meant to imply that they do.
Certainly some mutations trade off a harm against a benefit, sickle-cell anemia is the classic example, but that doesn’t mean all or even most of them do.
No, I don’t imply any connection to anencephaly. The point is just that many deleterious outcomes that we observe are a trade-off against something. In some cases we know against what—as you mentioned, sickle-cell anemia is an example. But in most cases we do not know. I would expect that a prior of “it’s a trade-off against some advantage, we don’t know yet which one” to hold as a rule, but I also expect to find some exceptions to it as well.
Not all but most very common obviously harmful mutations involve some kind of tradeoff or somehow fails to affect reproduction.
If something kills you in older age it’s free to spread, if something isn’t so terrible it can also spread through founder effects in a population but if some trait obviously hurts people at a young age but is still common it’s a good sign that it’s giving or did give some kind of advantage. .
These don’t seem to be related to anencephaly in particular? Not sure if you meant to imply that they do.
Certainly some mutations trade off a harm against a benefit, sickle-cell anemia is the classic example, but that doesn’t mean all or even most of them do.
No, I don’t imply any connection to anencephaly. The point is just that many deleterious outcomes that we observe are a trade-off against something. In some cases we know against what—as you mentioned, sickle-cell anemia is an example. But in most cases we do not know. I would expect that a prior of “it’s a trade-off against some advantage, we don’t know yet which one” to hold as a rule, but I also expect to find some exceptions to it as well.
Not all but most very common obviously harmful mutations involve some kind of tradeoff or somehow fails to affect reproduction.
If something kills you in older age it’s free to spread, if something isn’t so terrible it can also spread through founder effects in a population but if some trait obviously hurts people at a young age but is still common it’s a good sign that it’s giving or did give some kind of advantage. .
Is homosexuality very common, at 1-3%? This requires quantitative analysis.
1 in 30 of the population counts as very common in genetics terms.