Data from: The contribution of the mitochondrial genome to sex-specific fitness variance

Maternal inheritance of mitochondrial DNA (mtDNA) facilitates the evolutionary accumulation of mutations with sex-biased fitness effects. Whereas maternal inheritance closely aligns mtDNA evolution with natural selection in females, it makes it indifferent to evolutionary changes that exclusively benefit males. The constrained response of mtDNA to selection in males can lead to asymmetries in the relative contributions of mitochondrial genes to female versus male fitness variation. Here, we examine the impact of genetic drift and the distribution of fitness effects (DFE) among mutations – including the correlation of mutant fitness effects between the sexes – on mitochondrial genetic variation for fitness. We show how drift, genetic correlations, and skewness of the DFE determine the relative contributions of mitochondrial genes to male versus female fitness variance. When mutant fitness effects are weakly correlated between the sexes, and the effective population size is large, mitochondrial genes should contribute much more to male than to female fitness variance. In contrast, high fitness correlations and small population sizes tend to equalize the contributions of mitochondrial genes to female versus male variance. We discuss implications of these results for the evolution of mitochondrial genome diversity and the genetic architecture of female and male fitness.

线粒体DNA（mtDNA）的母系遗传，可推动携带性别偏向适合度效应的突变在进化过程中积累。母系遗传一方面使mtDNA的进化与雌性的自然选择紧密匹配，另一方面却令mtDNA的进化完全不受仅对雄性有利的演化变化的影响。雄性体内mtDNA对选择的响应受到约束，这会导致线粒体基因对雌性与雄性适合度变异的相对贡献产生不对称性。本研究考察了遗传漂变以及突变间的适合度效应分布（DFE）——包括不同性别间突变适合度效应的相关性——对线粒体基因适合度遗传变异的影响。我们阐明了遗传漂变、遗传相关性以及适合度效应分布的偏态性，如何决定线粒体基因对雄性与雌性适合度变异的相对贡献。当不同性别间的突变适合度效应相关性较弱、有效种群规模较大时，线粒体基因对雄性适合度变异的贡献应远高于雌性。反之，较高的适合度相关性与较小的种群规模，则会使线粒体基因对雌性与雄性适合度变异的贡献趋于均等。我们还讨论了上述结果对线粒体基因组多样性演化，以及雌性、雄性适合度遗传结构的启示。