Scott Alexander, who is a psychiatrist, discusses the tradeoffs versus failures of schizophrenia as a jumping off point to discuss the phenomenon of tradeoffs versus flat-out failures in genes and interventions. (The title must need editing - doesn't make any sense.) He makes the good distinction that sometimes it is not the expression of a gene that is ambiguous in its fitness, but the risk of it.
But cancer risk can also be elevated by tradeoffs: for example, with many asterisks and caveats, the higher a person’s risk of cancer, the lower their risk of certain degenerative diseases like Alzheimers, probably because cells can be set to either easy division (maximizing healing and growth) or limited division (minimizing cancer risk).
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Sickle-cell disease is apparently a side effect of an anti-malaria adaptation.
Nick Lane writes about this kind of tradeoff often in his popular science books about cellular biology. Birds, for instance, are fantastically good at limiting harmful free radicals in their cells and live a long time; the trade-off seems to be that they reproduce slowly and are so bad at tolerating temperature swings that most of them have to migrate seasonally. Rats reproduce like crazy but are little cancer machines, drowning in free radicals. It has to do with the advantages of tight cooperation between mitochondrial and nuclear DNA, which allows super-fit low-free-radical aerobic performance, as needed for flight, but which also triggers a quality-control mechanism that weeds out suboptimal embryos (i.e. ones with bad Mt/DNA matching) and therefore reduces fertility.
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