Garrido-Bautista Jorge, Comas Mar, Jowers Michael J, Smith Steve, Penn Dustin J, Bakkali Mohammed, Moreno-Rueda Gregorio
Department of Zoology, University of Granada, Granada 18071, Spain.
Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA.
R Soc Open Sci. 2024 Jun 12;11(6):240601. doi: 10.1098/rsos.240601. eCollection 2024 Jun.
Genetic differentiation between populations inhabiting ecologically different habitats might appear because of limited dispersal and gene flow, which may lead to patterns of phenotypic divergence and local adaptation. In this study, we use dispersal, genotypic (24 microsatellite loci) and phenotypic (body size and clutch size) data to analyse patterns of genetic structuring and phenotypic divergence in a blue tit () population inhabiting a continuous and heterogeneous woodland along a valley. The two slopes of the valley differ in their forest formations and environmental conditions. Findings showed that most blue tits reproduced within their natal slope. Accordingly, microsatellite analyses revealed that populations of blue tits established in the two slopes show subtle genetic differentiation. The two genetic populations diverged in clutch size, exceeding the level of differentiation expected based on genetic drift, hence suggesting divergent selection (or other processes promoting divergence) on this life-history trait. Our findings reveal that restricted dispersal and spatial heterogeneity may lead to genetic differentiation among bird populations at a surprisingly small scale. In this respect, it is worth highlighting that such differentiation occurs for an organism with high dispersal capacity and within a continuous woodland. Moreover, we show that small-scale ecological differences, together with limited gene flow, can result in selection favouring different phenotypes even within the same continuum population.
由于扩散受限和基因流，栖息在生态环境不同的栖息地中的种群之间可能会出现遗传分化，这可能导致表型分化和局部适应的模式。在本研究中，我们使用扩散、基因型（24个微卫星位点）和表型（体型和窝卵数）数据，来分析一个栖息在山谷中连续且异质林地的青山雀种群的遗传结构和表型分化模式。山谷的两个坡面在森林构成和环境条件方面存在差异。研究结果表明，大多数青山雀在其出生的坡面内繁殖。相应地，微卫星分析显示，在两个坡面建立的青山雀种群表现出细微的遗传分化。这两个遗传种群在窝卵数上存在差异，超过了基于遗传漂变预期的分化水平，因此表明在这个生活史性状上存在趋异选择（或其他促进分化的过程）。我们的研究结果表明，受限的扩散和空间异质性可能在惊人的小尺度上导致鸟类种群之间的遗传分化。在这方面，值得强调的是，这种分化发生在具有高扩散能力的生物体中，并且是在连续的林地内。此外，我们表明，即使在同一个连续种群内，小规模的生态差异以及有限的基因流也会导致选择有利于不同的表型。
