Cyr Frédéric, Angers Bernard
Group for Interuniversity Research in Limnology and Aquatic Environment, Département de Sciences Biologiques, Université de Montréal, 90 Vincent d'Indy, Montreal, QC, Canada.
Genetica. 2011 Dec;139(11-12):1417-28. doi: 10.1007/s10709-012-9640-2. Epub 2012 Mar 3.
Identification of the effects of historical processes on spatial genetic variation is of major importance in landscape genetics, especially in recent systems where the signal of recent isolation is often hardly perceptible. The goal of this study was to assess how differences in colonization patterns could influence spatial genetic variation using two centrarchidae species, the pumpkinseed sunfish (Lepomis gibbosus) and the rock bass (Ambloplites rupestris), from two adjacent drainage systems. The striking difference between the spatial genetic variations of the two species suggests completely opposite patterns of colonization. Rock bass colonized the drainage system from a downstream source, which resulted in a loss of diversity in upstream populations and a strong differentiation between drainage systems. In contrast, the reduction of genetic diversity and increase of differentiation toward downstream populations that were observed among sunfish populations suggest colonization from upstream to downstream. The colonization pattern observed in sunfish, which result in low differentiation between upstream most sites of the two drainages, leads to a false genetic signal of current inter-drainage gene flow. The present study demonstrates through empirical evidence that colonization patterns may impede the capacity to estimate current connectivity.
确定历史过程对空间遗传变异的影响在景观遗传学中至关重要，特别是在近期隔离信号往往难以察觉的现代系统中。本研究的目的是利用来自两个相邻排水系统的两种鲈形目鱼类，即蓝鳃太阳鱼（Lepomis gibbosus）和岩钝鲈（Ambloplites rupestris），评估定殖模式的差异如何影响空间遗传变异。这两个物种空间遗传变异的显著差异表明了完全相反的定殖模式。岩钝鲈从下游源头定殖到排水系统，这导致上游种群的多样性丧失以及排水系统之间的强烈分化。相比之下，在太阳鱼种群中观察到的遗传多样性降低和向下游种群分化增加表明是从上游向下游定殖。在太阳鱼中观察到的定殖模式导致两条排水系统最上游位点之间的低分化，从而产生了当前排水系统间基因流的错误遗传信号。本研究通过实证证据表明，定殖模式可能会阻碍估计当前连通性的能力。
