Redpath Museum, McGill University 859 Sherbrooke Street West, Montreal, H3A 0C4, QC, Canada.
Ecol Evol. 2013 Oct;3(12):4172-82. doi: 10.1002/ece3.787. Epub 2013 Sep 25.
Phenotypic differentiation is often interpreted as a result of local adaptation of individuals to their environment. Here, we investigated the skull morphological differentiation in 11 populations of the white-footed mouse (Peromyscus leucopus). These populations were sampled in an agricultural landscape in the Montérégie region (Québec, Canada), at the northern edge of the distribution of the white-footed mouse. We found a strong pattern of phenotypic differentiation matching the genetic structure across these populations. Landscape fragmentation and the presence of geographic barriers, in particular north-south oriented rivers, contribute to this differentiation and modulate the pattern of rapid ongoing northward range expansion of the white-footed mouse in response to climate warming. We conclude that while large rivers and postglacial recolonization routes have shaped the current pattern of distribution and differentiation of white-footed mouse populations, further local differentiation is occurring, at the scale of the landscape. We posit that the northern expansion of the white-footed mouse is achieved through successive independent founder events in a fragmented landscape at the northern range edge of the species. The phenotypic differentiation we observe is thus a result of a number of mechanisms operating at different spatial and temporal scales.
表型分化通常被解释为个体对环境的局部适应的结果。在这里，我们调查了 11 个白足鼠（Peromyscus leucopus）种群的头骨形态分化。这些种群是在加拿大魁北克蒙特利尔地区（Montérégie 地区）的农业景观中采样的，位于白足鼠分布范围的北部边缘。我们发现了一种与这些种群遗传结构相匹配的强烈表型分化模式。景观破碎化和地理障碍的存在，特别是南北走向的河流，促成了这种分化，并调节了白足鼠由于气候变暖而快速向北扩张的模式。我们的结论是，虽然大河流和冰后期的再殖民路线塑造了白足鼠种群当前的分布和分化模式，但在景观尺度上，进一步的局部分化正在发生。我们假设，白足鼠在物种北部范围边缘的破碎景观中，通过一系列独立的创始事件实现了向北扩张。我们观察到的表型分化是由在不同时空尺度上运作的多种机制共同作用的结果。
