Population Genomics of Infectious and Integrated Wolbachia pipientis Genomes in Drosophila ananassae.
Population Genomics of Infectious and Integrated Wolbachia pipientis Genomes in Drosophila ananassae.
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DOI：
10.1093/gbe/evv158
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发表时间：
2015-08-08
影响因子：
3.3
通讯作者：
Aquadro CF
中科院分区：
文献类型：
--
作者：
Choi JY;Bubnell JE;Aquadro CF
果蝇与其内共生体 Wolbachia pipientis 之间的共同进化有许多有趣的方面。例如，Drosophila ananassae 拥有两种形式的 W. pipientis 基因组：一种是感染性细菌基因组，另一种整合到宿主核基因组中。在这里，我们通过对 15 个具有感染性或整合性 wAna 基因组的 D. ananassae 菌株进行基因组测序，描述了感染 D. ananassae (wAna) 的 W. pipientis 的感染性和整合基因组。结果表明，传染性 wAna 基因组具有进化稳定的母体传播，表明与其宿主存在相对长期的共同进化。相比之下，整合的 wAna 基因组表现出类似假基因的特征，积累了许多变体，如果这些变体存在于感染性细菌基因组中，预计会产生有害影响。序列变异的系统基因组分析以及通过聚合酶链式反应对大的结构变异进行基因分型表明，八个传染性 wAna 基因组中存在多个 wAna 变异。相比之下，在非洲、南亚和南太平洋岛屿品系中检查的七个整合 wAna 基因组中只发现了一个 wAna 变体，这表明整合发生在单个传染性 wAna 基因组中一次，然后在地理上传播。进一步的分析表明，对于我们用整合的 wAna 基因组检查的所有 D. ananassae，大多数整合的 wAna 基因组区域至少有两个拷贝，表明双整合或单整合，然后是整合的基因组复制。 wAna 基因组重复整合在地理上广泛存在的潜在进化机制是一个有待回答的有趣问题。
Coevolution between Drosophila and its endosymbiont Wolbachia pipientis has many intriguing aspects. For example, Drosophila ananassae hosts two forms of W. pipientis genomes: One being the infectious bacterial genome and the other integrated into the host nuclear genome. Here, we characterize the infectious and integrated genomes of W. pipientis infecting D. ananassae (wAna), by genome sequencing 15 strains of D. ananassae that have either the infectious or integrated wAna genomes. Results indicate evolutionarily stable maternal transmission for the infectious wAna genome suggesting a relatively long-term coevolution with its host. In contrast, the integrated wAna genome showed pseudogene-like characteristics accumulating many variants that are predicted to have deleterious effects if present in an infectious bacterial genome. Phylogenomic analysis of sequence variation together with genotyping by polymerase chain reaction of large structural variations indicated several wAna variants among the eight infectious wAna genomes. In contrast, only a single wAna variant was found among the seven integrated wAna genomes examined in lines from Africa, south Asia, and south Pacific islands suggesting that the integration occurred once from a single infectious wAna genome and then spread geographically. Further analysis revealed that for all D. ananassae we examined with the integrated wAna genomes, the majority of the integrated wAna genomic regions is represented in at least two copies suggesting a double integration or single integration followed by an integrated genome duplication. The possible evolutionary mechanism underlying the widespread geographical presence of the duplicate integration of the wAna genome is an intriguing question remaining to be answered.