Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
Department of Earth and Environmental Sciences (DISAT), University of Milano Bicocca, Piazza della Scienza, 1, I-20126 Milan, Italy.
Sci Rep. 2017 Mar 31;7:45412. doi: 10.1038/srep45412.
Individuals often considerably differ in the timing of their life-cycle events, with major consequences for individual fitness, and, ultimately, for population dynamics. Phenological variation can arise from genetic effects but also from epigenetic modifications in DNA expression and translation. Here, we tested if CpG methylation at the poly-Q and 5'-UTR loci of the photoperiodic Clock gene predicted migration and breeding phenology of long-distance migratory barn swallows (Hirundo rustica) that were tracked year-round using light-level geolocators. Increasing methylation at Clock poly-Q was associated with earlier spring departure from the African wintering area, arrival date at the European breeding site, and breeding date. Higher methylation levels also predicted increased breeding success. Thus, we showed for the first time in any species that CpG methylation at a candidate gene may affect phenology and breeding performance. Methylation at Clock may be a candidate mechanism mediating phenological responses of migratory birds to ongoing climate change.
个体在其生命周期事件的时间上常常存在显著差异，这对个体适应性产生重大影响，并最终影响到种群动态。物候变化可能源于遗传效应，但也可能源于 DNA 表达和翻译的表观遗传修饰。在这里，我们通过使用光级地理定位器对全年进行跟踪的长距离迁徙的家燕（Hirundo rustica），测试了光周期时钟基因的 poly-Q 和 5'-UTR 位点的 CpG 甲基化是否可以预测迁徙和繁殖物候。Clock 基因 poly-Q 处的甲基化程度增加与春季离开非洲越冬区的时间提前、到达欧洲繁殖地的日期以及繁殖日期有关。较高的甲基化水平也预示着繁殖成功率的提高。因此，我们首次在任何物种中证明，候选基因的 CpG 甲基化可能会影响物候和繁殖表现。Clock 处的甲基化可能是一种候选机制，介导候鸟对正在进行的气候变化的物候响应。
