Shikano Takahito, Järvinen Antero, Marjamäki Paula, Kahilainen Kimmo K, Merilä Juha
Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland.
Kilpisjärvi Biological Station, University of Helsinki, Kilpisjärvi, Finland.
PLoS One. 2015 Oct 15;10(10):e0140344. doi: 10.1371/journal.pone.0140344. eCollection 2015.
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.
假定为中性的遗传标记的变异可以让我们了解当代种群的进化潜力、历史有效种群大小和系统地理学历史。我们研究了北欧斯堪的纳维亚北部六个本土内陆北极红点鲑（Salvelinus alpinus）种群中15个微卫星位点的遗传变异性，该物种在当地被视为近危物种。我们发现所有种群在遗传上高度分化（平均FST≈0.26）且相互隔离。有证据表明存在历史上的种群大小瓶颈，但近期没有。当代有效种群大小（Ne）的估计值在7到228之间，并且与历史上的Ne显著相关，但与湖泊大小无关。在一个面积为0.14公顷的池塘中，普查种群大小（NC）估计约为300只个体，该池塘的Ne最小（即Ne/NC = 0.02）。这个池塘和与之相连的湖泊中的遗传变异性严重降低，并且遗传和经验估计的迁移率都表明它们之间缺乏基因流动。因此，尽管目前数量繁荣，但一些北欧斯堪的纳维亚北部的种群似乎很容易进一步丧失遗传变异性，并且如果选择压力发生变化，它们适应的能力可能有限。
