Data from: Experimental test of genetic rescue in isolated populations of brook trout

Genetic rescue is an increasingly considered conservation measure to address genetic erosion associated with habitat loss and fragmentation. The resulting gene flow from facilitating migration may improve fitness and adaptive potential, but is not without risks (e.g., outbreeding depression). Here, we conducted a test of genetic rescue by translocating ten (five of each sex) brook trout (Salvelinus fontinalis) from a single source to four nearby and isolated stream populations. To control for the demographic contribution of translocated individuals, ten resident individuals (five of each sex) were removed from each recipient population. Prior to the introduction of translocated individuals, the two smallest above-barrier populations had substantially lower genetic diversity, and all populations had reduced effective number of breeders relative to adjacent below-barrier populations. In the first reproductive bout following translocation, 31 of 40 (78%) translocated individuals reproduced successfully. Translocated individuals contributed to more families than expected under random mating and generally produced larger full-sibling families. We observed relatively high (>20%) introgression in three of the four recipient populations. The translocations increased genetic diversity of recipient populations by 45% in allelic richness and 25% in expected heterozygosity. Additionally, strong evidence of hybrid vigour was observed through significantly larger body sizes of hybrid offspring relative to resident offspring in all recipient populations. Continued monitoring of these populations will test for negative fitness effects beyond the first generation. However, these results provide much-needed experimental data to inform the potential effectiveness of genetic rescue-motivated translocations.遗传拯救（Genetic rescue）是当前日益受到重视的保护措施，用于应对栖息地丧失与破碎化引发的遗传侵蚀。由促进个体迁移所产生的基因流，或可提升种群适合度与适应性潜力，但同样存在诸多风险（例如远交衰退（outbreeding depression））。本研究通过将10条溪鳉（Salvelinus fontinalis，雌雄各5只）从单一源种群移殖至4个邻近且隔离的溪流种群中，开展了遗传拯救效果的验证实验。为控制移殖个体的种群统计学贡献，我们从每个接收种群中移除了10个本地个体（雌雄各5只）。在引入移殖个体前，两个规模最小的坝上种群的遗传多样性显著更低，且所有接收种群的有效繁殖种群数量均低于相邻的坝下种群。在移殖后的首次繁殖周期中，40条移殖个体中有31条（占比78%）成功完成繁殖。移殖个体参与构建的家系数量多于随机交配情境下的预期值，且通常形成更大的全同胞家系。我们在4个接收种群中的3个内观察到了较高（>20%）的基因渐渗（introgression）水平。此次移殖使接收种群的遗传多样性得到显著提升：等位基因丰富度提升45%，期望杂合度提升25%。此外，所有接收种群中的杂交后代体型均显著大于本地后代，这为杂种优势提供了强有力的实验证据。对这些种群的持续监测，将用于检验第一代之后是否会出现负面适合度效应。不过，本研究结果提供了亟需的实验数据，可为基于遗传拯救目的的种群移殖的潜在有效性提供科学参考。