Data from: Genetic variability and structuring of Arctic charr (Salvelinus alpinus) populations in northern Fennoscandia

Variation in presumably neutral genetic markers can inform us about evolvability, historical effective population sizes and phylogeographic history of contemporary populations. We studied genetic variability in 15 microsatellite loci in six native landlocked Arctic charr (Salvelinus alpinus) populations in northern Fennoscandia, where this species is considered near threatened. We discovered that all populations were genetically highly (mean FST ≈ 0.26) differentiated and isolated from each other. Evidence was found for historical, but not for recent population size bottlenecks. Estimates of contemporary effective population size (Ne) ranged from seven to 228 and were significantly correlated with those of historical Ne but not with lake size. A census size (NC) was estimated to be approximately 300 individuals in a pond (0.14 ha), which exhibited the smallest Ne (i.e. Ne/NC = 0.02). Genetic variability in this pond and a connected lake is severely reduced, and both genetic and empirical estimates of migration rates indicate a lack of gene flow between them. Hence, albeit currently thriving, some northern Fennoscandian populations appear to be vulnerable to further loss of genetic variability and are likely to have limited capacity to adapt if selection pressures change.假定中性的遗传标记的变异，可为我们解析当代种群的演化潜力、历史有效种群大小以及系统地理历史。本研究针对芬诺斯坎迪亚北部6个土著陆封型北极红点鲑（Salvelinus alpinus）种群的15个微卫星位点开展遗传变异分析，该物种在此区域被评估为近危物种。研究发现，所有种群间均存在高度遗传分化（平均遗传分化系数FST≈0.26）且彼此隔离。本研究检测到历史种群瓶颈的信号，但未发现近期种群瓶颈的相关证据。当代有效种群大小（Ne）的估计值介于7至228之间，且与历史有效种群大小的估计值显著相关，但与湖泊面积无显著关联。在一处面积为0.14公顷的池塘中，实际种群数量（NC）的估计值约为300个个体，该种群的Ne值最小（即Ne/NC=0.02）。该池塘及其连通湖泊的遗传变异均大幅降低，且遗传迁移率与实际迁移率的估算结果均显示二者间不存在基因流。因此，尽管部分芬诺斯坎迪亚北部的北极红点鲑种群目前种群状态良好，但它们仍极易发生遗传多样性的进一步丧失，且在选择压力改变时，其适应能力可能较为有限。