Data from: The double edged sword: the demographic consequences of the evolution of self-fertilisation

Phylogenies indicate that the transition from outcrossing to selfing is frequent, with selfing populations being more prone to extinction. The rates of transition to selfing and extinction, acting on different timescales, could explain the observed distributions of extant selfing species among taxa. However, phylogenetic and theoretical studies consider these mechanisms independently, i.e. transitions do not cause extinction. Here, we theoretically explore the demographic consequences of the evolution of self-fertilization. Deleterious mutations and mutations modifying the selfing rate are recurrently introduced and the number of offspring depends on individual fitness, allowing for a demographic feedback. We show that mutational meltdowns can be triggered in populations evolving near strict selfing. Populations having survived the demographic crash are more stable than ancestral outcrossing populations once deleterious mutations are purged. The relatively rapid time-scales in which extinctions occur indicate that during evolutionary transitions the accumulation of deleterious mutations may not be the cause of extinctions observed on longer time scales, which in turn could lead to the underestimation of transition rates from outcrossing to selfing.系统发育（phylogenies）研究表明，异交向自交的演化过渡频发，且自交种群更易走向灭绝。自交过渡速率与灭绝速率作用于不同的时间尺度，这可解释现存自交物种在各分类群中的分布格局。然而，现有系统发育学与理论研究均独立考量这两种机制，即假定演化过渡并不会引发灭绝。本研究从理论层面探究自交演化的种群统计学效应：研究中反复引入有害突变与修饰自交率的突变，且后代数量由个体适合度决定，由此形成种群统计反馈。研究结果显示，在接近严格自交的种群中，可能触发突变崩溃（mutational meltdowns）。在有害突变被清除后，经历种群统计崩溃并存活的种群，其稳定性较祖先异交种群更高。灭绝事件发生的时间尺度相对较短，这表明在演化过渡过程中，有害突变的积累或许并非长期尺度上观测到的灭绝事件的诱因——这一结论反过来可能导致对异交向自交过渡速率的低估。