Genomic evidence of hybridization between two independent invasions of European green crab (Carcinus maenas) in the Northwest Atlantic

Invasive species have been associated with significant negative impacts in their introduced range often outcompeting native species, yet the long-term evolutionary dynamics of biological invasions are not well understood. Hybridization, either among waves of invasion or between native and introduced populations, could alter the ecological and evolutionary impacts of invasions yet has rarely been studied in marine invasive species. The European green crab (Carcinus maenas) invaded eastern North America twice from northern and southern locations in its native range. Here we examine the frequency of hybridization among these two distinct invasions at locations from New Jersey, USA to Newfoundland, Canada using restriction-site associated DNA sequencing (RAD-seq), microsatellite loci, and COI mtDNA sequences. We used Bayesian clustering and hybrid assignment analyses to investigate hybridization between the northern and southern populations. Of the samples analyzed, six locations contain...外来入侵物种在其入侵分布区通常会造成显著负面影响，多通过竞争排斥本土物种实现，但学界对生物入侵的长期演化动力学机制仍缺乏深入认知。杂交事件既可能发生于不同入侵波之间，也可出现于本土种群与入侵种群之间，均有可能改变生物入侵的生态与演化效应，但目前针对海洋入侵物种的此类杂交研究仍较为稀缺。欧洲绿蟹（Carcinus maenas）曾从其原生分布区的南北两个区域先后两次入侵北美东部海域。本研究以美国新泽西州至加拿大纽芬兰岛沿岸的采样区域为对象，采用限制性位点相关DNA测序（restriction-site associated DNA sequencing, RAD-seq）、微卫星位点（microsatellite loci）以及细胞色素氧化酶I线粒体DNA（COI mtDNA）序列，对这两次独立入侵事件之间的杂交频率展开分析。本研究运用贝叶斯聚类分析（Bayesian clustering）与杂交归属分析（hybrid assignment analyses）方法，探究南北两类种群间的杂交情况。在已分析的采样样本中，共有6个采样点包含