But that sort of thing is pretty rare, so the claim that it happens in a particular species with no such obvious mechanism (or indeed in practically all animals) is a little harder to swallow.
I think it’s important that the AP theory holds even if the early-life gain is very small and the late-life cost is very large; that should broaden the list of potential ways to achieve that trade-off.
More generally, the idea of antagonistic pleiotropy as a general phenomenon doesn’t seem that surprising to me: trade-offs are everywhere in biology, and if one side of a trade-off is underweighted by selection then it’ll get shafted. It’s basically just overfitting: it would be surprising if the optimal set-up for growing, surviving and reproducing over a span of (say) 20 years were also the optimal set-up for doing the same over (say) 100 years, and natural selection is almost entirely optimising for the former.
I meant that I would expect a mutation that causes tissue repair function to degrade with age to decrease fitness (slightly) overall, since there’s no obvious connection to some beneficial effect earlier in life.
One potential response to this is that this is systems thinking rather than genes thinking. Many genes do lots of things across lots of systems, so you could see a mutation that improves functionality in a way that’s relevant to one system early in life, at a cost to another system in late life.
(I’m personally more of a fan of relaxed purifying selection, which seems like the more general and less contingent theory, but I do think antagonistic pleiotropy theory is solid enough that finding more concrete examples of it wouldn’t surprise me.)
I think it’s important that the AP theory holds even if the early-life gain is very small and the late-life cost is very large; that should broaden the list of potential ways to achieve that trade-off.
More generally, the idea of antagonistic pleiotropy as a general phenomenon doesn’t seem that surprising to me: trade-offs are everywhere in biology, and if one side of a trade-off is underweighted by selection then it’ll get shafted. It’s basically just overfitting: it would be surprising if the optimal set-up for growing, surviving and reproducing over a span of (say) 20 years were also the optimal set-up for doing the same over (say) 100 years, and natural selection is almost entirely optimising for the former.
One potential response to this is that this is systems thinking rather than genes thinking. Many genes do lots of things across lots of systems, so you could see a mutation that improves functionality in a way that’s relevant to one system early in life, at a cost to another system in late life.
(I’m personally more of a fan of relaxed purifying selection, which seems like the more general and less contingent theory, but I do think antagonistic pleiotropy theory is solid enough that finding more concrete examples of it wouldn’t surprise me.)