Hidden genetic variance contributes to increase the short-term adaptive potential of selfing populations

Standing genetic variation is considered a major contributor to the adaptive potential of species. The low heritable genetic variation observed in self-fertilising populations has led to the hypothesis that species with this mating system would be less likely to adapt. However, a non-negligible amount of cryptic genetic variation for polygenic traits, accumulated through negative linkage disequilibrium, could prove to be an important source of standing variation in self-fertilising species. To test this hypothesis we simulated populations under stabilizing selection subjected to an environmental change. We demonstrate that, when the mutation rate is high (but realistic), selfing populations are better able to store genetic variance than outcrossing populations through genetic associations, notably due to the reduced effective recombination rate associated with predominant selfing. Following an environmental shift, this diversity can be partially remobilized, which increases the additive...现存遗传变异（standing genetic variation）被认为是物种适应潜力的主要来源。自交种群中观测到的可遗传遗传变异水平较低，由此提出假说：具备该交配系统的物种，其适应能力往往更弱。然而，通过负连锁不平衡（negative linkage disequilibrium）积累的、针对多基因性状的大量不可忽视的隐性遗传变异（cryptic genetic variation），可能成为自交物种现存遗传变异的重要来源。为验证该假说，我们对处于稳定选择（stabilizing selection）压力下且经历环境变化的种群进行了模拟。研究表明，当突变率（mutation rate）处于较高且符合实际的水平时，自交种群可通过遗传关联比异交种群更高效地储存遗传方差，这主要源于主导自交所伴随的有效重组率（effective recombination rate）降低。在环境转变（environmental shift）后，这类遗传多样性可被部分重新激活，进而提升加性……