Genetic and morphometric divergence in threespine stickleback in the Chignik catchment, Alaska

Divergent selection pressures induced by different environmental conditions typically lead to variation in life history, behaviour and morphology. When populations are locally adapted to their current environment, selection may limit movement into novel sites, leading to neutral and adaptive genetic divergence in allopatric populations. Subsequently, divergence can be reinforced by development of pre- or post-zygotic barriers to gene flow. The threespine stickleback, Gasterosteus aculeatus, is a primarily marine fish that has invaded freshwater repeatedly in postglacial times. After invasion, the established freshwater populations typically show rapid diversification of several traits as they become reproductively isolated from their ancestral marine population. In this paper we examine the genetic and morphometric differentiation between sticklebacks living in an open system comprising a brackish water lagoon, two freshwater lakes, and connecting rivers. By applying a set of microsatel...

不同环境条件诱导产生的趋异选择压力，通常会导致生物在生活史、行为与形态方面出现变异。当种群对当前环境形成本地适应后，选择作用可能会限制其向新生境扩散，进而使异域种群产生中性与适应性遗传分化。后续，合子前或合子后基因流障碍的形成，会进一步强化这种分化。三棘刺鱼（Gasterosteus aculeatus）是一类主要营海洋生活的鱼类，在冰期后曾多次入侵淡水生境。成功定植的淡水种群通常会快速出现多项性状的分化，并与其祖先海洋种群产生生殖隔离。本文中，我们对栖息于某开放系统中的刺鱼种群开展了遗传与形态计量分化分析，该系统包含一处咸水泻湖、两座淡水湖泊以及连通各生境的河流。通过应用一组微卫星……