Data from: Genetic structure of Daphnia galeata populations in Eastern China

This study presents the first examination of the genetic structure of Daphnia longispina complex populations in Eastern China. Only one species, D. galeata, was present across the eight investigated lakes; as identified by taxon assignment using allelic variation at 15 microsatellite loci. Three genetically differentiated D. galeata subgroups emerged independent of the type of statistical analysis applied. Thus, Bayesian clustering, discriminant analysis based on results from factorial correspondence analysis, and UPGMA clustering consistently showed that populations from two neighbouring lakes were genetically separated from a mixture of genotypes found in other lakes, which formed another two subgroups. Clonal diversity was high in all D. galeata populations, and most samples showed no deviation from Hardy-Weinberg equilibrium, indicating that clonal selection had little effect on the genetic diversity. Overall, populations did not cluster by geographical origin. Further studies will show if the observed pattern can be explained by natural colonization processes or by recent anthropogenic impact on predominantly artificial lakes.

本研究首次针对中国东部长棘溞复合群（Daphnia longispina complex）的种群遗传结构展开系统性分析。经基于15个微卫星位点（microsatellite loci）等位基因变异的类群鉴定，本次调查的8个湖泊中仅存在盔形溞（D. galeata）一个物种。无论采用何种统计分析方法，均可检测到三个遗传分化显著的盔形溞亚群。具体而言，贝叶斯聚类（Bayesian clustering）、基于对应因子分析（factorial correspondence analysis）结果的判别分析，以及非加权组平均法聚类（UPGMA clustering）均得到一致结论：两座相邻湖泊的种群与其余湖泊的基因型混合种群存在遗传分化，而后者可进一步划分为两个亚群，三者共同构成全部三个盔形溞遗传亚群。所有盔形溞种群均表现出较高的克隆多样性（clonal diversity），且多数样本未偏离哈迪-温伯格平衡（Hardy-Weinberg equilibrium），表明克隆选择对种群遗传多样性的影响较为有限。总体而言，种群的聚类结果与其地理起源并无显著关联。未来相关研究将进一步探明，本次观测到的遗传格局究竟是由自然定殖过程所形成，还是近期人为活动对以人工湖为主的湖泊系统产生影响所致。