PREMISE The mating system has profound consequences, not only for ecology and evolution, but also for the conservation of threatened or endangered species. Unfortunately, small populations are difficult to study owing to limits on sample size and genetic marker diversity. Here, we estimated mating system parameters in three small populations of an island plant using genomic genotyping. Although self-incompatible (SI) species are known to often set some self-seed, little is known about how "leaky SI" affects selfing rates in nature or the role that multiple paternity plays in small populations. METHODS We generalized the BORICE mating system program to determine the siring pattern within maternal families. We applied this algorithm to maternal families from three populations of Tolpis succulenta from Madeira Island and genotyped the progeny using RADseq. We applied BORICE to estimate each individual offspring as outcrossed or selfed, the paternity of each outcrossed offspring, and the level of inbreeding of each maternal plant. RESULTS Despite a functional self-incompatibility system, these data establish T. succulenta as a pseudo-self-compatible (PSC) species. Two of 75 offspring were strongly indicated as products of self-fertilization. Despite selfing, all adult maternal plants were fully outbred. There was high differentiation among and low variation within populations, consistent with a history of genetic isolation of these small populations. There were generally multiple sires per maternal family. Twenty-two percent of sib contrasts (between outcrossed offspring within maternal families) shared the same sire. CONCLUSIONS Genome-wide genotyping, combined with appropriate analytical methods, enables estimation of mating system and multiple paternity in small populations. These data address questions about the evolution of reproductive traits and the conservation of threatened populations.

中文翻译：

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全基因组基因分型估计岛屿物种 Tolpis succulenta 的交配系统参数和亲子关系

前提 交配系统具有深远的影响，不仅对生态和进化，而且对受威胁或濒危物种的保护。不幸的是，由于样本量和遗传标记多样性的限制，很难研究小种群。在这里，我们使用基因组基因分型估计了岛屿植物的三个小种群的交配系统参数。尽管已知自交不相容 (SI) 物种通常会设置一些自交种子，但人们对“泄漏的 SI”如何影响自然界的自交率或多父系在小种群中所起的作用知之甚少。方法 我们推广了 BORICE 交配系统程序，以确定母系内的后代模式。我们将此算法应用于来自马德拉岛的三个 Tolpis succulenta 种群的母系家庭，并使用 RADseq 对后代进行基因分型。我们应用 BORICE 来估计每个单独的后代是异交还是自交，每个异交后代的父系，以及每个母本植物的近交水平。结果 尽管有一个功能性的自交不亲和系统，但这些数据将 T. succulenta 确立为一种假自交 (PSC) 物种。75 个后代中有两个强烈表明是自体受精的产物。尽管自交，所有成年母本植物都是完全远交的。种群之间的高度分化和低变异，与这些小种群的遗传隔离历史一致。每个母系通常有多个父亲。22% 的同胞对比（母系内异种后代之间）共享同一父系。结论 全基因组基因分型，结合适当的分析方法，能够估计小群体的交配系统和多父系。这些数据解决了有关生殖特征进化和受威胁种群保护的问题。