Data from: Genetic impacts of Anacapa deer mice reintroductions following rat eradication

The Anacapa deer mouse is an endemic subspecies that inhabits Anacapa Island, part of Channel Islands National Park. Anacapa is a chain of three small islands (East, Middle and West). In this study, we used mitochondrial DNA (mtDNA) cytochrome c oxidase subunit II gene (COII) and ten microsatellite loci to evaluate the levels of genetic differentiation and variation in ~1400 Anacapa deer mice sampled before and after a black rat (Rattus rattus) eradication campaign that included trapping, captive holding and reintroduction of deer mice. We also compared levels of genetic variation in Anacapa deer mice to those of a nearby mainland population. Both mitochondrial and microsatellite analyses indicated significant differentiation between Anacapa deer mice and mainland mice, and genetic variability of mainland mice was significantly higher than Anacapa mice even prior to reintroduction. We also found that East, Middle and West Anacapa mice were genetically differentiated from each other, but translocation of mice among islands resulted in the East population becoming less distinct as a result of management. Levels of heterozygosity were similar before and after management. However, numerous private alleles in the founder populations were not observed after reintroduction and shifts in allele frequencies occurred, indicating that the reintroduced populations experienced substantial genetic drift. Surprisingly, two mitochondrial haplotypes observed in an earlier study of Anacapa deer mice were lost in the 20 years prior to the rat eradication program, leaving only a single haplotype in Anacapa deer mice.

阿纳卡帕鹿鼠（Anacapa deer mouse）是一种特有亚种，栖息于海峡群岛国家公园的组成部分——阿纳卡帕群岛。阿纳卡帕群岛由三座小型岛屿组成，分别为东岛、中岛与西岛。本研究选取线粒体DNA（mtDNA）细胞色素c氧化酶亚基II基因（COII）与10个微卫星位点作为分子标记，对约1400只阿纳卡帕鹿鼠的遗传分化与变异水平展开评估。这些样本采集于针对黑家鼠（Rattus rattus）的灭除行动前后，该灭除方案包含诱捕、圈养以及鹿鼠的再引入环节。本研究同时将阿纳卡帕鹿鼠的遗传变异水平与邻近的大陆种群进行了对比。线粒体与微卫星分析均显示，阿纳卡帕鹿鼠与大陆小鼠之间存在显著的遗传分化；且即便在再引入实施之前，大陆小鼠的遗传变异水平也显著高于阿纳卡帕鹿鼠。研究同时发现，阿纳卡帕群岛的东岛、中岛与西岛鹿鼠种群彼此间存在遗传分化，但通过岛屿间的个体移植（管理措施），东岛种群的遗传独特性有所降低。管理实施前后，种群的杂合度水平基本保持一致。不过，奠基种群中存在的大量私有等位基因在再引入后未被检测到，且等位基因频率发生了偏移，这表明再引入种群经历了显著的遗传漂变。令人意外的是，此前一项针对阿纳卡帕鹿鼠的研究中发现的两种线粒体单倍型，在灭鼠计划实施前的20年间已丢失，如今阿纳卡帕鹿鼠仅存一种线粒体单倍型。