Genetic and phenotypic differentiation among Galaxias maculatus populations in a Patagonian postglacial lake system

Understanding the influence of landscape features on population differentiation is fundamental to evolutionary biology studies. We examined spatial patterns of genetic and phenotypic variability among Galaxias maculatus populations in a complex of four postglacial lakes in northwestern Patagonia differing in size and connectivity among them. A hierarchical Bayesian analysis grouped the individuals collected from 11 localities into 3 genetic clusters, first defining the populations of the two large lakes and separating the two small lakes in subsequent analysis. Genetic structuring was restricted within large lakes. It is known that the larval stage of Galaxias maculatus migrate to the limnetic zone of Patagonian lakes, possibly exerting an homogenizing effect on gene flow within lakes. Gene flow asymmetry and divergences among lakes can be explained by a combination of landscape characteristics and the presence of predators in the short streams that connect them. Individuals from the sm...

阐明景观特征对种群分化的影响，是进化生物学（evolutionary biology）研究的基础性核心课题。本研究以巴塔哥尼亚西北部4个冰后湖泊组成的复杂湖群为对象，该湖群内各湖泊的体型与连通性存在差异，研究团队针对该湖群内斑纹南乳鱼（Galaxias maculatus）的种群，分析了其遗传与表型变异的空间分布模式。通过分层贝叶斯分析（hierarchical Bayesian analysis），研究团队将11个采样点采集的个体划分为3个遗传聚类群：首先区分出两个大型湖泊的种群，后续分析进一步将两个小型湖泊的种群区分开来。遗传结构的分化仅局限于大型湖泊内部。已有研究证实，斑纹南乳鱼的幼体阶段会迁移至巴塔哥尼亚湖泊的敞水带（limnetic zone），该过程可能对湖泊内部的基因流产生均质化效应。湖泊间的基因流不对称性与种群分化，可通过景观特征与连接各湖泊的短小溪流中捕食者的存在共同解释。采自sm……的个体