Bioenergetic consequences of sex-specific mitochondrial DNA evolution

Doubly uniparental inheritance (DUI) represents a notable exception to the general rule of strict maternal inheritance (SMI) of mitochondria in metazoans. This system entails the coexistence of two mitochondrial lineages (F- and M-type) transmitted separately through oocytes and sperm, thence providing an unprecedented opportunity for the mitochondrial genome to evolve adaptively for male functions. In this study, we explored the impact of a sex-specific mitochondrial evolution upon gamete bioenergetics of DUI and SMI bivalve species, comparing the activity of key-enzymes of glycolysis, fermentation, fatty acid metabolism, tricarboxylic acid cycle, oxidative phosphorylation and antioxidant metabolism. Our findings suggest reorganized bioenergetic pathways in DUI gametes compared to SMI gametes. This generally results in a decreased enzymatic capacity in DUI sperm with respect to DUI oocytes, a limitation especially prominent at the terminus of the electron transport system. This bioener...双重单亲遗传（Doubly uniparental inheritance, DUI）是后生动物中线粒体严格母系遗传（strict maternal inheritance, SMI）通用规则的一项显著例外。该系统存在两种分别通过卵母细胞与精子传递的线粒体谱系（F型与M型）的共存状态，从而为线粒体基因组针对雄性功能开展适应性演化提供了前所未有的契机。本研究探讨了性别特异性线粒体演化对DUI与SMI双壳类物种配子生物能学的影响，对比分析了糖酵解、发酵、脂肪酸代谢、三羧酸循环、氧化磷酸化及抗氧化代谢关键酶的活性。研究结果表明，与SMI配子相比，DUI配子的生物能通路发生了重构。总体而言，相较于DUI卵母细胞，DUI精子的酶促能力有所下降，这一限制在电子传递链末端尤为突出。该生物能