ON THE EVOLUTION OF CYTOPLASMIC INCOMPATIBILITY IN HAPLODIPLOID SPECIES
ON THE EVOLUTION OF CYTOPLASMIC INCOMPATIBILITY IN HAPLODIPLOID SPECIES
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DOI：
10.1111/j.0014-3820.2002.tb01424.x
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发表时间：
2002-06
期刊：
影响因子：
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通讯作者：
M. Egas;F. Vala;J. Breeuwer
中科院分区：
文献类型：
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作者：
M. Egas;F. Vala;J. Breeuwer
沃尔巴克氏体内共生体最神秘的性操纵是细胞质不相容（CI）：感染的雄性与未感染的雌性生殖不相容。本文以单倍体物种为研究对象，对种群动态和进化理论进行了扩展。首先，我们关注沃尔巴克氏体感染在人群中的入侵阈值问题。对小种群中感染动态的模拟表明，仅仅假定是漂移入侵（或人口“意外”）是不够的。我们提出了几个有希望的替代方案，可能促进沃尔巴克氏体在未感染人群中的入侵：性别比例效应、元群体结构和其他适应度补偿效应。包括沃尔巴克氏体的性别比例效应，当受感染的雌性产生的受感染的后代比未受感染的雌性产生的未受感染的后代更多时，就会允许入侵。一些对单倍体物种的研究表明存在这种性别比例效应。我们分析的简单元种群模型预测，鉴于被感染者是更好的“入侵者”，未被感染者必须是更好的“殖民者”，以维持被感染和未感染斑块的共存。这种情况似乎更适用于因捕食（或寄生）而局部灭绝的物种，而不适用因过度开发其资源而局部灭绝的物种。最后，我们分析了一旦种群被感染，单倍体中CI的进化。进化并不取决于CI的类型（雌性死亡率或雄性产量），而仅仅取决于降低适应度成本和/或提高传播效率。我们的模型为增加我们对CI种群和进化动态的理解提供了新的视角。
Abstract The most enigmatic sexual manipulation by Wolbachia endosymbionts is cytoplasmic incompatibility (CI): infected males are reproductively incompatible with uninfected females. In this paper, we extend the theory on population dynamics and evolution of CI, with emphasis on haplodiploid species. First, we focus on the problem of the threshold to invasion of the Wolbachia infection in a population. Simulations of the dynamics of infection in small populations show that it does not suffice to assume invasion by drift alone (or demographic “accident”). We propose several promising alternatives that may facilitate invasion of Wolbachia in uninfected populations: sex-ratio effects, meta population structure, and other fitness-compensating effects. Including sex-ratio effects of Wolbachia allows invasion whenever infected females produce more infected daughters than uninfected females produce uninfected daughters. Several studies on haplodiploid species suggest the presence of such sex-ratio effects. The simple metapopulation model we analyzed predicts that, given that infecteds are better “invaders,” uninfecteds must be better “colonizers” to maintain coexistence of infected and uninfected patches. This condition seems more feasible for species that suffer local extinction due to predation (or parasitization) than for species that suffer local extinction due to overexploiting their resource(s). Finally, we analyze the evolution of CI in haplodiploids once a population has been infected. Evolution does not depend on the type of CI (female mortality or male production), but hinges solely on decreasing the fitness cost and/or increasing the transmission efficiency. Our models offer new perspectives for increasing our understanding of the population and evolutionary dynamics of CI.