Do North Atlantic Eels show parallel patterns of spatially varying selection?

Background: The two North Atlantic eel species, the European and the American eel, represent an ideal system in which to study parallel selection patterns due to their sister species status and the presence of ongoing gene flow. A panel of 80 coding-gene SNPs previously analyzed in American eel was used to genotype European eel individuals (glass eels) from 8 sampling locations across the species distribution. We tested for single-generation signatures of spatially varying selection in European eel by searching for elevated genetic differentiation using FST-based outlier tests and by testing for significant associations between allele frequencies and environmental variables. Results: We found signatures of possible selection at a total of 11 coding-gene SNPs. Candidate genes for local selection constituted mainly genes with a major role in metabolism as well as defense genes. Contrary to what has been found for American eel, only 2 SNPs in our study correlated with differences in temper...研究背景：北大西洋鳗鱼的两个类群——欧洲鳗鲡与美洲鳗鲡——因互为姊妹物种且存在持续基因流，成为探究平行选择模式的理想实验体系。本研究采用此前针对美洲鳗鲡分析得到的包含80个编码基因单核苷酸多态性（Single Nucleotide Polymorphism, SNP）位点的检测面板，对分布范围内8个采样点的欧洲鳗鲡个体（玻璃鳗阶段）进行基因分型。通过基于固定指数（Fixation Index, FST）的离群位点检测筛选遗传分化升高的位点，并检验等位基因频率与环境变量间的显著关联，以此探究欧洲鳗鲡的单代空间异质选择信号。 研究结果：本研究共在11个编码基因SNP位点上发现了潜在选择信号。参与局部适应选择的候选基因主要为在代谢过程中发挥核心作用的基因以及免疫防御相关基因。与针对美洲鳗鲡的已有研究结论相悖，本研究中仅有2个SNP位点与温度（原文表述未完整）相关的差异存在关联。