The endosymbiont Wolbachia can manipulate arthropod host reproduction by inducing cytoplasmic incompatibility (CI), which results in embryonic mortality when infected males mate with uninfected females. A CI-driven invasion of Wolbachia can result in a selective sweep of associated mitochondrial haplotype. The co-inheritance of Wolbachia and host mitochondrial DNA can therefore provide significant information on the dynamics of an ongoing Wolbachia invasion. Therefore, transition zones (i.e., regions where a Wolbachia strain is currently spreading from infected to uninfected populations) represent an ideal area to investigate the relationship between Wolbachia and host mitochondrial haplotype. Here, we studied Wolbachia-mitochondrial haplotype associations in the European cherry fruit fly, Rhagoletis cerasi, in two transition zones in the Czech Republic and Hungary, where the CI-inducing strain wCer2 is currently spreading. The wCer2-infection status of 881 individuals was compared with the two known R. cerasi mitochondrial haplotypes, HT1 and HT2. In accordance with previous studies, wCer2-uninfected individuals were associated with HT1, and wCer2-infected individuals were mainly associated with HT2. We found misassociations only within the transition zones, where HT2 flies were wCer2-uninfected, suggesting the occurrence of imperfect maternal transmission. We did not find any HT1 flies that were wCer2-infected, suggesting that Wolbachia was not acquired horizontally. Our study provides new insights into the dynamics of the early phase of a Wolbachia invasion.

中文翻译：

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Rhagoletis cerasi 过渡种群中的 Wolbachia-线粒体 DNA 关联

内共生体Wolbachia可以通过诱导细胞质不相容性 (CI) 来操纵节肢动物宿主的繁殖，当受感染的雄性与未感染的雌性交配时，这会导致胚胎死亡。CI 驱动的Wolbachia入侵可导致相关线粒体单倍型的选择性扫描。因此，沃尔巴克氏体和宿主线粒体 DNA的共同遗传可以提供有关正在进行的沃尔巴克氏体入侵动态的重要信息。因此，过渡区（即Wolbachia菌株目前从受感染人群传播到未感染人群的区域）代表了研究Wolbachia之间关系的理想区域和宿主线粒体单倍型。在这里，我们在捷克共和国和匈牙利的两个过渡区研究了欧洲樱桃果蝇Rhagoletis cerasi中的Wolbachia - 线粒体单倍型关联，其中 CI 诱导菌株w Cer2 目前正在传播。将 881 个个体的w Cer2 感染状态与两种已知的R. cerasi线粒体单倍型 HT1 和 HT2 进行了比较。根据之前的研究，w Cer2 未感染的个体与 HT1 相关，而w Cer2 感染的个体主要与 HT2 相关。我们仅在 HT2 苍蝇所在的过渡区内发现错误关联Cer2-未感染，表明发生了不完全母体传播。我们没有发现任何被 Cer2 感染的 HT1 果蝇，这表明Wolbachia不是水平获得的。我们的研究为沃尔巴克氏体入侵早期的动态提供了新的见解。