My premise is that there was a technologically advanced human-equivalent civilisation that eventually obliterated itself with weapons of mass destruction, but left behind a survivalist sect obsessed with genetic engineering, so that when the next wave of technologically advanced humans came along thousands of years later, it perceived those survivors as "primitive" and "feral" but endowed with Tarzan-like superpowers based on extremely evolved instincts that continue to adapt extremely fast between generations.
The remnant humans had engineered themselves to be able to "read" DNA like a sort of language, and thus be consciously able to maximise its offspring's Darwinian advantage by adding new instinctive abilities; ultimately, though, it's based on mate selection, and their mate selection involves an all-consuming mental effort resulting in behaviours similar to autism. I'd also like, for narrative purposes, to have this DNA-reading ability be blood-based and create an association with vampirism. I'm vaguely aware that it's not necessarily the optimal design from the scientific standpoint.
My question is, how generally plausible is "wiring" a nominally human brain to be able to interpret and, to a degree, manipulate DNA using the faculty of taste as input, and what would be the natural limitations if the general principle does work.