Biparental chloroplast inheritance leads to rescue from cytonuclear incompatibility

Although organelle inheritance is predominantly maternal across animals and plants, biparental chloroplast inheritance has arisen multiple times in the angiosperms. Biparental inheritance has the potential to impact the evolutionary dynamics of cytonuclear incompatibility, interactions between nuclear and organelle genomes that are proposed to be among the earliest types of genetic incompatibility to arise in speciation.
We examine the interplay between biparental inheritance and cytonuclear incompatibility in Campanulastrum americanum, a plant species exhibiting both traits. We first determine patterns of chloroplast inheritance in genetically similar and divergent crosses, and then associate inheritance with hybrid survival across multiple generations.
There is substantial biparental inheritance in C. americanum. The frequency of biparental inheritance is greater in divergent crosses and in the presence of cytonuclear incompatibility. Biparental inheritance helps to mitigate cytonuc...

尽管在动物与植物中，细胞器遗传（organelle inheritance）多遵循母系遗传（maternal inheritance）模式，但被子植物（angiosperms）类群中已多次独立演化出双亲型叶绿体遗传（biparental chloroplast inheritance）策略。双亲型遗传可对核质不相容性（cytonuclear incompatibility）的演化动力学产生影响——核基因组与细胞器基因组间的互作被视为物种形成（speciation）过程中最早出现的遗传不相容类型之一。
本研究以同时具备双亲型叶绿体遗传与核质不相容性特征的美洲风铃草（Campanulastrum americanum）为研究材料，探讨二者之间的互作关系。我们首先明确遗传相似度各异的杂交组合（crosses）中的叶绿体遗传模式，随后分析多世代尺度下遗传模式与杂种存活率（hybrid survival）之间的关联。
美洲风铃草中存在显著的双亲型叶绿体遗传现象。双亲型遗传的发生频率在遗传差异较大的杂交组合以及存在核质不相容性的情境下更高。双亲型遗传有助于缓解核质...