Data from: Identifying patterns of dispersal, connectivity, and selection in the sea scallop, Placopecten magellanicus, using RAD-seq derived SNPs

Understanding patterns of dispersal and connectivity among marine populations can directly inform fisheries conservation and management. Advances in high-throughput sequencing offer new opportunities for estimating marine connectivity. We used Restriction-site Associated DNA sequencing to examine dispersal and realized connectivity in the sea scallop Placopecten magellanicus, an economically important marine bivalve. Based on 245 individuals sampled range-wide at 12 locations from Newfoundland to the Mid-Atlantic Bight we identified and genotyped 7163 Single Nucleotide Polymorphisms; 112 (1.6%) were identified as outliers potentially under directional selection. Bayesian clustering revealed a discontinuity between northern and southern samples and latitudinal clines in allele frequencies were observed in 42.9% of the outlier loci and in 24.6% of neutral loci. Dispersal estimates derived using these clines and estimates of linkage disequilibrium imply limited dispersal; 373.1 ± 407.0 km (mean ± SD) for outlier loci and 641.0 ± 544.6 km (mean ± SD) for neutral loci. Our analysis suggests restricted dispersal compared to the species range (>2000 km) and that dispersal and effective connectivity differ. These observations support the hypothesis that limited effective dispersal structures scallop populations along eastern North America. These findings can help refine the appropriate scale of management and conservation in this commercially valuable species.

解析海洋种群间的扩散模式与连通性特征，可为渔业保护与管理提供直接依据。高通量测序（high-throughput sequencing）技术的进步，为海洋连通性的评估提供了全新契机。本研究采用限制性酶切位点相关DNA测序（Restriction-site Associated DNA sequencing）技术，对兼具重要经济价值的海洋双壳类物种——美洲海扇（Placopecten magellanicus）的扩散与实际连通性展开研究。本研究在覆盖该物种全分布范围的12个采样位点（从纽芬兰至中大西洋湾）中共采集245个个体，最终鉴定并完成基因分型的单核苷酸多态性（Single Nucleotide Polymorphisms，SNP）位点共计7163个，其中112个（占比1.6%）被鉴定为可能受定向选择作用的离群位点。贝叶斯聚类分析显示，北部与南部采样样本间存在遗传分化断点；同时，在42.9%的离群位点以及24.6%的中性位点中，均观测到等位基因频率的纬度梯度分布模式。基于上述纬度梯度与连锁不平衡（linkage disequilibrium）估算得到的扩散距离表明，该物种的扩散能力有限：离群位点对应的平均扩散距离为373.1±407.0 km（平均值±标准差，mean ± SD），中性位点则为641.0±544.6 km（平均值±标准差，mean ± SD）。相较于该物种的分布范围（>2000 km），本研究分析结果显示其扩散受到显著限制，且扩散与有效连通性二者存在差异。上述研究结果支持"有限的有效扩散塑造了北美东部海域美洲海扇种群结构"这一假说。本研究结果可为该经济价值重要物种的合理管理与保护尺度优化提供科学依据。