Spontaneous emergence of a new wolbachia phenotype
Spontaneous emergence of a new wolbachia phenotype
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DOI：
10.1111/j.1558-5646.2007.00180.x
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发表时间：
2007-09-01
期刊：
影响因子：
3.3
通讯作者：
Jaenike, John
中科院分区：
文献类型：
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作者：
Jaenike, John
沃尔巴克氏菌是地球上分布最广的共生体之一。它们通过控制寄主繁殖的各种方式在种群内传播，包括细胞质不亲和性(CI)、杀雄(MK)、孤雌生殖和雌性化。系统发育分析表明，沃尔巴克氏菌有可能在表型上经历快速的进化变化，例如从CI到MK，尽管这种分析没有揭示这种转换发生的速度，也没有揭示中间表型的性质。在这里，我展示了从CI到MK的转变几乎可以在进化时间尺度上瞬间发生。通过杂交和回交的自然过程，将一株在其自然寄主果蝇中引起CI的沃尔巴克氏菌菌株导入到其姊妹种小果蝇中。在一些品系中，感染这种沃尔巴克氏菌株会导致基本完全的MK，导致全雌性孵化，而在另一些品系中，对后代的性别比没有影响。亚奎尼亚石斑菌和雷氏石斑菌之间的杂交表明，对MK的抗性是显性的、常染色体的、多基因的，并取决于合子而不是母本的基因型。小金龟子的MK是不寻常的，因为感染雌性的雄性后代在幼虫阶段死亡，而不是作为胚胎死亡。这些发现提示MK和CI可能具有相似的潜在分子基础。
Wolbachia are among the most widespread symbionts on the earth. They spread within populations by various means of manipulating host reproduction, including cytoplasmic incompatibility (CI), male-killing (MK), parthenogenesis, and feminization. Phylogenetic analyses indicate that Wolbachia have the potential to undergo rapid evolutionary change in phenotype, for example, from CI to MK, although such analyses do not reveal the rate at which such transitions occur, nor the nature of the intermediate phenotypes. Here I show that a transition from CI to MK can occur almost instantaneously on an evolutionary time scale. A Wolbachia strain that causes CI in its natural host, Drosophila recens, was introgressed to its sister species D. subquinaria via the natural processes of hybridization and backcrossing. In some strains of D. subquinaria, infection with this Wolbachia strain caused essentially complete MK, resulting in all-female broods, whereas in other strains, there was no effect on offspring sex ratio. Crosses within and between D. subquinaria and D. recens revealed that resistance to MK is dominant, autosomal, multigenic, and dependent on zygotic, not maternal, genotype. MK in D. subquinaria is unusual in that the male offspring of infected females die during the larval stage, not as embryos. These findings suggest that MK and CI may share a similar underlying molecular basis.