Genophagy (literally 'gene eating') is the now-outdated idea in genetics that dominant alleles 'swamp' and gradually replace recessive alleles over generations, leading to the eventual extinction of recessive phenotypes. The name is derived from the idea that dominant alleles 'eat' recessive alleles out of the gene pool. This concept has been (incorrectly) used to make claims that certain recessive phenotypes in humans, such as blonde hair colour, may eventually be wiped out.

The idea has since been discredited and replaced by the Hardy-Weinberg Principle, which asserts that gene pools are inherently stable over generational time. They are only destabilised by the action of evolutionary mechanisms such as mutation, selection, drift and gene flow - and these processes of destabilisation can affect the frequency of dominant alleles and recessive alleles equally.