Wolbachia Acquisition by Drosophila yakuba-Clade Hosts and Transfer of Incompatibility Loci Between Distantly Related Wolbachia
Wolbachia Acquisition by Drosophila yakuba-Clade Hosts and Transfer of Incompatibility Loci Between Distantly Related Wolbachia
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DOI：
10.1534/genetics.119.302349
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发表时间：
2019-08-01
期刊：
影响因子：
3.3
通讯作者：
Turelli, Michael
中科院分区：
文献类型：
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作者：
Cooper, Brandon S.;Vanderpool, Dan;Turelli, Michael
母体传播的沃尔巴克氏体感染约一半的昆虫物种，但沃尔巴克氏体收购的主要模式仍然不确定。物种特异性协会可能是古老的，沃尔巴克氏体和宿主共同多样化（即，分支获得），或相对年轻并通过水平转移或渐渗获得。三个果蝇yakuba-clade宿主[（D. santomea，山核桃D. yakuba）D. teissieri]的分歧类似于3百万年，目前杂交的西非岛屿比奥科和圣多美托姆。每个物种都是多态性的几乎相同的沃尔巴克氏体，导致弱细胞质不相容性（CI）减少卵孵化时，未感染的女性与感染的男性交配。D. yakuba-clade Wolbachia与wMel关系密切，在D.黑腹果蝇我们使用草案沃尔巴克氏体和线粒体基因组证明，D。Wolbachia和线粒体的yakuba-clade遗传倾向于遵循宿主核遗传。然而，大约一半的D。在Sao托姆杂交区内外取样的santomea个体，已经渗入D.雅库巴线粒体。线粒体和沃尔巴克氏体都拥有比大部分宿主核基因组更近的共同祖先，排除了分支沃尔巴克氏体的收购。一般一致的沃尔巴克氏体和线粒体基因组表明，水平传播是罕见的，但不同的相对速率的分子分歧复杂的基于时序图的统计检验。在wMel中引起CI的基因座在D中被破坏。yakuba-clade Wolbachia;但是预测引起CI的第二组基因座位于相同的WO原噬菌体区域。这些替代CI基因座似乎已经从远亲沃尔巴克氏体水平获得，通过侧翼沃尔巴克氏体特异性ISWpi 1转座子介导的转移。
Maternally transmitted Wolbachia infect about half of insect species, yet the predominant mode(s) of Wolbachia acquisition remains uncertain. Species-specific associations could be old, with Wolbachia and hosts codiversifying (i.e., cladogenic acquisition), or relatively young and acquired by horizontal transfer or introgression. The three Drosophila yakuba-clade hosts [(D. santomea, D. yakuba) D. teissieri] diverged similar to 3 MYA and currently hybridize on the West African islands Bioko and Sao Tome. Each species is polymorphic for nearly identical Wolbachia that cause weak cytoplasmic incompatibility (CI)-reduced egg hatch when uninfected females mate with infected males. D. yakuba-clade Wolbachia are closely related to wMel, globally polymorphic in D. melanogaster. We use draft Wolbachia and mitochondrial genomes to demonstrate that D. yakuba-clade phylogenies for Wolbachia and mitochondria tend to follow host nuclear phylogenies. However, roughly half of D. santomea individuals, sampled both inside and outside of the Sao Tome hybrid zone, have introgressed D. yakuba mitochondria. Both mitochondria and Wolbachia possess far more recent common ancestors than the bulk of the host nuclear genomes, precluding cladogenic Wolbachia acquisition. General concordance of Wolbachia and mitochondrial phylogenies suggests that horizontal transmission is rare, but varying relative rates of molecular divergence complicate chronogram-based statistical tests. Loci that cause CI in wMel are disrupted in D. yakuba-clade Wolbachia; but a second set of loci predicted to cause CI are located in the same WO prophage region. These alternative CI loci seem to have been acquired horizontally from distantly related Wolbachia, with transfer mediated by flanking Wolbachia-specific ISWpi1 transposons.