Recently Nick Norwitz pointed out that there was a variant of the ApoC3 gene that was associated with longer life (https://open.substack.com/pub/staycuriousmetabolism/p/the-untold-story-of-apoc3-and-human). Why then isn't that variant more common? Well you might think you'd be fitter, in the survival of the fittest game, if you lived longer. Unfortunately your genes don't especially care about you, they care about themselves. And what they want is for you to live long enough to do grandparenting, then depart and stop using resources that your genes would prefer to see go to your descendents.
So now we see that aging works like light coloured skin. There isn't one gene for white skin. There are lots of genes which affect skin colour, and we get a cocktail of these depending on how far our ancestors lived from the equator, plus what particular ones have appeared in that area in the past.
Similarly with aging: genes which make your life too short are selected against because your grandchildren lack that extra bit of care that human (and orca) babies need. But genes which make you live too long are also selected against because then your great grandchildren and other descendents have less resources, after you are no longer needed for grandparenting.
What this means from a practical point of view, in our modern world that is awash with resources for humans, is that aging is not a malfunction. It isn't caused by errors but by deliberate choice. We can track down a lot of those choices by looking at the DNA of people who live a long time. And the problems that these genetic choices make for individuals might be relatively easy to fix.
