I hadn’t heard the transposon theory of aging before. If true, that would explain why aging hasn’t been selected out by evolution: the transposons themselves have evolved, under different incentives than their host genome’s incentives.
Hold that thought—there’s a post on evolution of aging coming up pretty soon. It’s one of the better-understood areas, since we can get a ton of information by comparing across species.
https://apomorphic.com/2020/01/12/why-we-age-2-nonadaptive presents a theory on that. Tldr (mostly from memory) would be that with no biological aging, we still have more kids when we’re young, so evolution cares more about us when we’re young, so there’s very little selection pressure against mutations that only damage us when we’re old, or especially which help us when we’re young and harm us when we’re old.
Thanks Phil. I should probably just put these on LessWrong to be honest.
The lens-growth phenomenon sounds like it might be a neat case of antagonistic pleiotropy as applied to developmental rates: a process calibrated to give good results in early adulthood might be selected for even if it gets wildly out of whack in later life. IIRC Williams gives the example of male Fiddler crabs, whose major claw grows faster than the rest of the body: the difference is calibrated to give them big sexy (but still manageable) claws in early adulthood but can severely impede movement in late life (I have not independently validated this example). One could imagine something similar happening here.
I hadn’t heard the transposon theory of aging before. If true, that would explain why aging hasn’t been selected out by evolution: the transposons themselves have evolved, under different incentives than their host genome’s incentives.
Hold that thought—there’s a post on evolution of aging coming up pretty soon. It’s one of the better-understood areas, since we can get a ton of information by comparing across species.
https://apomorphic.com/2020/01/12/why-we-age-2-nonadaptive presents a theory on that. Tldr (mostly from memory) would be that with no biological aging, we still have more kids when we’re young, so evolution cares more about us when we’re young, so there’s very little selection pressure against mutations that only damage us when we’re old, or especially which help us when we’re young and harm us when we’re old.
Thanks Phil. I should probably just put these on LessWrong to be honest.
The lens-growth phenomenon sounds like it might be a neat case of antagonistic pleiotropy as applied to developmental rates: a process calibrated to give good results in early adulthood might be selected for even if it gets wildly out of whack in later life. IIRC Williams gives the example of male Fiddler crabs, whose major claw grows faster than the rest of the body: the difference is calibrated to give them big sexy (but still manageable) claws in early adulthood but can severely impede movement in late life (I have not independently validated this example). One could imagine something similar happening here.