Institut National de la Recherche Agronomique, Laboratoire de Génétique des Poissons, Domaine de Vilvert, F-78352 Jouy en Josas, France.
J Hered. 2010 May-Jun;101(3):270-83. doi: 10.1093/jhered/esp130. Epub 2010 Feb 4.
Human-mediated biological invasions constitute interesting case studies to understand evolutionary processes, including the role of founder effects. Population expansion of newly introduced species can be highly dependant on barriers caused by landscape features, but identifying these barriers and their impact on genetic structure is a relatively recent concern in population genetics and ecology. Salmonid populations of the Kerguelen Islands archipelago are a favorable model system to address these questions as these populations are characterized by a simple history of introduction, little or no anthropogenic influence, and demographic monitoring since the first introductions. We analyzed genetic variation at 10 microsatellite loci in 19 populations of brown trout (Salmo trutta L.) in the Courbet Peninsula (Kerguelen Islands), where the species, introduced in 3 rivers only, has colonized the whole water system in 40 years. Despite a limited numbers of introductions, trout populations have maintained a genetic diversity comparable with what is found in hatchery or wild populations in Europe, but they are genetically structured. The main factor explaining the observed patterns of genetic diversity is the history of introductions, with each introduced population acting as a source for colonization of nearby rivers. Correlations between environmental and genetic parameters show that within each "source population" group, landscape characteristics (type of coast, accessibility of river mouth, distances between rivers, river length ...) play a role in shaping directions and rates of migration, and thus the genetic structure of the colonizing populations.
人类介导的生物入侵构成了有趣的案例研究，有助于理解进化过程，包括奠基者效应的作用。新引入物种的种群扩张高度依赖于由景观特征造成的障碍，但在种群遗传学和生态学中，确定这些障碍及其对遗传结构的影响是一个相对较新的关注点。在 Kerguelen 群岛，鲑鱼种群是一个很好的模型系统，可以用来解决这些问题，因为这些种群的引入历史简单，几乎没有人为影响，并且自首次引入以来就进行了人口监测。我们分析了在 Courbet 半岛（Kerguelen 群岛）的 19 个棕鳟（Salmo trutta L.）种群中的 10 个微卫星基因座的遗传变异，在这些种群中，该物种仅在 3 条河流中被引入，40 年内就已经占领了整个水系。尽管引入的数量有限，但鳟鱼种群保持的遗传多样性与在欧洲的孵化场或野生种群中发现的遗传多样性相当，但它们存在遗传结构。解释遗传多样性观察模式的主要因素是引入历史，每个引入的种群都作为附近河流的殖民来源。环境和遗传参数之间的相关性表明，在每个“源种群”群体中，景观特征（海岸类型、河口可达性、河流之间的距离、河流长度等）在塑造迁移方向和速度方面发挥了作用，从而影响了殖民种群的遗传结构。
