Mitochondrial genetic effects on reproductive success: signatures of positive intrasexual, but negative intersexual pleiotropy

Theory predicts that maternal inheritance of mitochondria will facilitate the accumulation of mtDNA mutations that are male biased, or even sexually antagonistic, in effect. While there are many reported cases of mtDNA mutations conferring cytoplasmic male sterility in plants, historically it was assumed such mutations would not persist in the streamlined mitochondrial genomes of bilaterian metazoans. Intriguingly, recent cases of mitochondrial variants exerting male-biases in effect have come to light in bilaterians. These cases aside, it remains unknown whether the mitochondrial genetic variation affecting phenotypic expression, and in particular reproductive performance, in bilaterians is routinely comprised of sex-biased or sex-specific variation. If selection consistently favours mtDNA variants that augment female fitness, but at cost to males, this could shape patterns of pleiotropy and lead to negative intersexual correlations across mtDNA haplotypes. Here, we show that genetic v...