Data from: The evolution of obligate sex: the roles of sexual selection and recombination

The evolution of sex is one of the greatest mysteries in evolutionary biology. An even greater mystery is the evolution of obligate sex, particularly when competing with facultative sex and not with complete asexuality. Here, we develop a stochastic simulation of an obligate allele invading a facultative population, where males are subject to sexual selection. We identify a range of parameters where sexual selection can contribute to the evolution of obligate sex: Especially when the cost of sex is low, mutation rate is high, and the facultative individuals do not reproduce sexually very often. The advantage of obligate sex becomes larger in the absence of recombination. Surprisingly, obligate sex can take over even when the population has a lower mean fitness as a result. We show that this is due to the high success of obligate males that can compensate the cost of sex.有性生殖的演化是演化生物学领域最核心的未解谜团之一。专性有性生殖（obligate sex）的演化更是一大核心未解谜题，尤其是当该演化过程与兼性有性生殖（facultative sex）而非完全无性生殖（asexuality）竞争的场景下。本研究构建了一套随机模拟（stochastic simulation）模型，用于模拟专性有性生殖等位基因（allele）入侵兼性有性生殖种群的演化过程，该种群中的雄性个体需经受性选择（sexual selection）。我们筛选出了一系列可使性选择（sexual selection）推动专性有性生殖演化的参数区间：尤其当有性生殖代价较低、突变率较高，且兼性有性生殖个体极少进行有性繁殖时。当不存在重组（recombination）时，专性有性生殖的演化优势会更为显著。令人意外的是，即便最终种群的平均适合度（fitness）有所降低，专性有性生殖仍可占据种群主导地位。我们的研究表明，这一现象源于专性有性生殖雄性个体极高的繁殖成功率，该成功率可抵消有性生殖的代价。