I found the Slate Star Codex article about uric acid interesting [1]. The bit about this gene:
> About ten million years ago, the common ancestor of apes and humans got a mutation that broke uricase, causing uric acid levels to rise. The mutation spread very quickly, suggesting that evolution _really_ wanted primates to have lots of uric acid for some reason. Since discovering this, scientists have been trying to figure out exactly what that reason was, with most people thinking it’s probably an antioxidant or neuroprotectant or something else helpful if you’re trying to evolve giant brains.
Maybe it functioned as a pheromone somehow (or pheromone precursor) and was aided by sexual selection: stinkiest mates were more attractive and reproduced more. Hehe.
Or might make your flesh pungent and not tasty to predators. The 'stinkiest' fish in the world[1] has high levels of urea (so high that its toxic, and while not uric acid these two molecules are related and both are options in metabolic pathways for processing ammonia) and before eating, hákarl needs to be dried in ice sheds in the artic circle for 3 months. Even then it's acquired taste.
Still, it seems unlikely primates were hunted by some unknown predator in such large numbers, for evolution to select for those with slightly more pungent flesh to deter such predation, but ... who knows? :P ;) xx
> About ten million years ago, the common ancestor of apes and humans got a mutation that broke uricase, causing uric acid levels to rise. The mutation spread very quickly, suggesting that evolution _really_ wanted primates to have lots of uric acid for some reason. Since discovering this, scientists have been trying to figure out exactly what that reason was, with most people thinking it’s probably an antioxidant or neuroprotectant or something else helpful if you’re trying to evolve giant brains.
[1] https://slatestarcodex.com/2020/04/27/give-yourself-gout-for...