Data from: Regional environmental pressure influences population differentiation in turbot (Scophthalmus maximus)

Unravelling the factors shaping the genetic structure of mobile marine species is challenging due to the high potential for gene flow. However, genetic inference can be greatly enhanced by increasing the genomic, geographic or environmental resolution of population genetic studies. Here we investigated the population structure of turbot (Scophthalmus maximus) by screening 17 random and gene-linked markers in 999 individuals at 290 geographical locations throughout the Northeast Atlantic Ocean. A seascape genetics approach with the inclusion of high resolution oceanographic data was used to quantify the association of genetic variation with spatial, temporal and environmental parameters. Neutral loci identified three subgroups: an Atlantic group, a Baltic Sea group and one on the Irish Shelf. The inclusion of loci putatively under selection suggested an additional break in the North Sea, subdividing southern from northern Atlantic individuals. Environmental and spatial seascape variables correlated marginally with neutral genetic variation, but explained significant proportions (respectively 8.7 % and 10.3 %) of adaptive genetic variation. Environmental variables associated with outlier allele frequencies included salinity, temperature, bottom shear stress, dissolved oxygen concentration and depth of the pycnocline. Furthermore, levels of explained adaptive genetic variation differed markedly among basins (3% vs 12% in the North and Baltic Sea, respectively). We suggest that stable environmental selection pressure contributes to relatively strong local adaptation in the Baltic Sea. Our seascape genetic approach using a large number of sampling locations and associated oceanographic data proved useful for the identification of population units as the basis of management decisions.

由于基因交流潜力极高，解析移动性海洋物种的遗传结构形成机制极具挑战。然而，通过提升群体遗传学研究的基因组、地理或环境分辨率，可极大优化遗传推断结果。本研究以大菱鲆（turbot，*Scophthalmus maximus*）为研究对象，对遍布东北大西洋290个地理采样点的999个个体，开展了17个随机位点与基因连锁位点的筛查分型。本研究采用纳入高分辨率海洋水文数据的景观遗传学（seascape genetics）方法，量化遗传变异与空间、时间及环境参数之间的关联。中性位点分析共鉴定出三个遗传亚群：大西洋群、波罗的海群以及爱尔兰陆架群。纳入疑似受选择的位点后，分析结果显示北海区域存在额外的遗传分化分界，将大西洋个体划分为南部与北部类群。景观遗传学环境与空间变量与中性遗传变异的相关性较弱，但可分别解释8.7%与10.3%的适应性遗传变异。与等位基因频率异常位点相关的环境变量包括盐度、水温、底切应力、溶解氧浓度以及密度跃层深度。此外，不同海域的适应性遗传变异解释率存在显著差异：北海与波罗的海的解释率分别为3%与12%。本研究推测，稳定的环境选择压力是波罗的海区域形成较强局部适应性的重要原因。本研究采用的景观遗传学方法，依托大量采样点位与配套海洋水文数据，可有效鉴定种群单元，为管理决策提供科学依据。