Voillemot M, Rougemont Q, Roux C, Pannell J R
Department of Ecology and Evolution, Biophore/Sorge, University of Lausanne, Lausanne, Switzerland.
Institut de Biologie Intégrative et des Systèmes (IBIS), University of Laval, Québec City, Québec, Canada.
J Evol Biol. 2018 Jan;31(1):136-147. doi: 10.1111/jeb.13209. Epub 2017 Dec 8.
Many angiosperms prevent inbreeding through a self-incompatibility (SI) system, but the loss of SI has been frequent in their evolutionary history. The loss of SI may often lead to an increase in the selfing rate, with the purging of inbreeding depression and the ultimate evolution of a selfing syndrome, where plants have smaller flowers with reduced pollen and nectar production. In this study, we used approximate Bayesian computation (ABC) to estimate the timing of divergence between populations of the plant Linaria cavanillesii that differ in SI status and in which SI is associated with low inbreeding depression but not with a transition to full selfing or a selfing syndrome. Our analysis suggests that the mixed-mating self-compatible (SC) population may have begun to diverge from the SI populations around 2810 generation ago, a period perhaps too short for the evolution of a selfing syndrome. We conjecture that the SC population of L. cavanillesii is at an intermediate stage of transition between outcrossing and selfing.
许多被子植物通过自交不亲和（SI）系统来防止近亲繁殖，但在其进化历史中，SI的丧失却屡见不鲜。SI的丧失可能常常导致自交率上升，同时消除近亲繁殖衰退，并最终进化出自交综合征，即植物花朵变小，花粉和花蜜产量降低。在本研究中，我们使用近似贝叶斯计算（ABC）来估计植物卡瓦尼利亚柳穿鱼不同种群之间的分化时间，这些种群在SI状态上存在差异，且SI与低近亲繁殖衰退相关，但与完全自交或自交综合征的转变无关。我们的分析表明，混合交配的自交亲和（SC）种群可能在大约2810代以前就开始与SI种群分化，这段时间可能太短，不足以进化出自交综合征。我们推测，卡瓦尼利亚柳穿鱼的SC种群正处于异交与自交之间过渡的中间阶段。
