Immonen E, Collet M, Goenaga J, Arnqvist G
Evolutionary Biology Centre, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
Master BioSciences, Department of Biology, École Normale Supérieure of Lyon, Lyon, France.
Heredity (Edinb). 2016 Mar;116(3):338-47. doi: 10.1038/hdy.2015.112. Epub 2016 Jan 6.
Mitochondria are involved in ageing and their function requires coordinated action of both mitochondrial and nuclear genes. Epistasis between the two genomes can influence lifespan but whether this also holds for reproductive senescence is unclear. Maternal inheritance of mitochondria predicts sex differences in the efficacy of selection on mitonuclear genotypes that should result in differences between females and males in mitochondrial genetic effects. Mitonuclear genotype of a focal individual may also indirectly affect trait expression in the mating partner. We tested these predictions in the seed beetle Callosobruchus maculatus, using introgression lines harbouring distinct mitonuclear genotypes. Our results reveal both direct and indirect sex-specific effects of mitonuclear epistasis on reproductive ageing. Females harbouring coadapted mitonuclear genotypes showed higher lifetime fecundity due to slower senescence relative to novel mitonuclear combinations. We found no evidence for mitonuclear coadaptation in males. Mitonuclear epistasis not only affected age-specific ejaculate weight, but also influenced male age-dependent indirect effects on traits expressed by their female partners (fecundity, egg size, longevity). These results demonstrate important consequences of sex-specific mitonuclear epistasis for both mating partners, consistent with a role for mitonuclear genetic constraints upon sex-specific adaptive evolution.
线粒体与衰老有关，其功能需要线粒体基因和核基因的协同作用。两个基因组之间的上位性可以影响寿命，但这是否也适用于生殖衰老尚不清楚。线粒体的母系遗传预示着对线粒体核基因型选择效率的性别差异，这应该会导致雌性和雄性在线粒体遗传效应上的差异。一个焦点个体的线粒体核基因型也可能间接影响其交配伴侣的性状表达。我们利用携带不同线粒体核基因型的渐渗系，在黄斑豆象中检验了这些预测。我们的结果揭示了线粒体核上位性对生殖衰老的直接和间接性别特异性影响。与新的线粒体核组合相比，具有协同适应的线粒体核基因型的雌性由于衰老较慢，一生的繁殖力更高。我们没有发现雄性线粒体核协同适应的证据。线粒体核上位性不仅影响特定年龄的射精重量，还影响雄性年龄依赖性的对其雌性伴侣所表达性状（繁殖力、卵大小、寿命）的间接影响。这些结果证明了性别特异性线粒体核上位性对两个交配伴侣的重要影响，这与线粒体核遗传限制在性别特异性适应性进化中的作用一致。
