Adaptive evolution during an ongoing range expansion: the invasive bank vole (Myodes glareolus) in Ireland.

Range expansions are extremely common, but have only recently begun to attract attention in terms of their genetic consequences. As populations expand, demes at the wave front experience strong genetic drift, which is expected to reduce genetic diversity and potentially cause 'allele surfing', where alleles may become fixed over a wide geographic area even if their effects are deleterious. Previous simulation models show that range expansions can generate very strong selective gradients on dispersal, reproduction, competition and immunity. To investigate the effects of range expansion on genetic diversity and adaptation, we studied the population genomics of the bank vole (Myodes glareolus) in Ireland. The bank vole was likely introduced in the late 1920s and is expanding its range at a rate of Ì´2.5 km yr-1. Using Genotyping by Sequencing (GBS), we genotyped 281 bank voles at 5,979 SNP loci. Fourteen sample sites were arranged in three transects running from the introduction site to the...物种分布范围扩张现象极为普遍，但直至近年，其遗传学效应才逐渐受到学界关注。随着种群扩张，扩张前沿的同类群会经历强烈的遗传漂变，该过程将降低遗传多样性，并可能引发“等位基因冲浪（allele surfing）”现象：即即便等位基因存在有害效应，仍可在广阔地理范围内实现固定。既往模拟研究表明，物种分布范围扩张可对扩散、繁殖、竞争及免疫相关性状产生极强的选择梯度。为探究物种分布范围扩张对遗传多样性与适应性演化的影响，本研究针对爱尔兰境内的岸田鼠（bank vole，学名*Myodes glareolus*）开展种群基因组学分析。该物种约于20世纪20年代末被引入爱尔兰，目前正以约2.5公里/年的速度扩张分布范围。本研究采用测序分型（Genotyping by Sequencing，GBS）技术，对281只岸田鼠的5979个单核苷酸多态性（SNP）位点完成基因分型。研究共设置14个采样点，沿三条从引入位点出发的样带分布，延伸至……