Relative rates of evolution of male-beneficial nuclear compensatory mutations and male-harming Mother's Curse mitochondrial alleles.

Mother's Curse alleles represent a significant source of potential male fitness defects. The maternal inheritance of mutations with the pattern of sex-specific fitness effects, s♀>0>s♂, allows Mother's Curse alleles to spread through a population even though they reduce male fitness. Although the mitochondrial genomes of animals contain only a handful of protein-coding genes, mutations in many of these genes have been shown to have a direct effect on male fertility.