Interspecific hybridization and island colonization history, not rarity, most strongly affect the genetic diversity in a clade of Mascarene-endemic trees

Many factors shape the genetic diversity of island-endemic trees, with important implications for conservation. Oceanic island-endemic lineages undergo an initial founding bottleneck during the colonization process and subsequently accumulate diversity following colonization. Moreover, many island endemics occur in small populations and are further threatened by anthropogenic factors that cause population declines, making them susceptible to losses in genetic diversity through genetic drift, inbreeding, and bottlenecks. However, life-history traits commonly found in trees, such as outcrossing mechanisms, long lifespans, and a propensity for interspecific hybridization, may help buffer against losses of genetic variation. To assess the relative importance of colonization history, rarity, and distribution in shaping genetic diversity of island-endemic trees, we conducted a comparative population genomic analysis of 13 species of Diospyros (Ebenaceae) endemic to the Mascarene Islands that ...诸多因素共同塑造了岛屿特有树木的遗传多样性，这对物种保护工作具有重要指导意义。海洋岛屿特有支系在定殖过程中会经历初始奠基者瓶颈效应，随后在成功定殖后逐步积累遗传多样性。此外，多数岛屿特有物种的种群规模普遍偏小，且会受到引发种群衰退的人为因素的进一步威胁，使其极易因遗传漂变、近交及瓶颈效应而发生遗传多样性丧失。然而，树木普遍具备的生活史特征——诸如异交机制、较长寿命以及种间杂交倾向——或可帮助缓冲遗传变异的丢失。为评估定殖历史、种群稀有性与分布格局在塑造岛屿特有树木遗传多样性过程中的相对重要性，我们针对马斯克林群岛特有的13种柿属（Diospyros，柿科Ebenaceae）植物开展了比较种群基因组分析，……