Identifying genetic variation involved in thermal adaptation is likely to yield insights into how species adapt to different climates. Physiological and behavioural responses associated with overwintering (e.g. torpor) are thought to serve important functions in climate adaptation. In this study, we use two isolated Peromyscus leucopus lineages on the northern margin of the species range to identify SNPs showing a strong environmental association and test for evidence of parallel evolution. We found signatures of clinal selection in each lineage, but evidence of parallelism was limited, with only two SNPs showing parallel allele frequencies across transects. These parallel SNPs map to a gene involved in protection against iron-dependent oxidative stress (Fxn) and to a gene with unknown function but containing a forkhead-associated domain (Fhad1). Furthermore, within transects, we find significant clinal patterns in genes enriched for functions associated with glycogen homeostasis, synaptic function, intracellular Ca2+ balance, H3 histone modification, as well as the G2/M transition of cell division. Our results are consistent with recent literature on the cellular and molecular basis of climate adaptation in small mammals and provide candidate genomic regions for further study.

中文翻译：

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白足鼠（Peromyscus leucopus）北缘沿气候梯度选择的基因组特征

识别热适应中涉及的遗传变异可能会深入了解物种如何适应不同的气候。与越冬相关的生理和行为反应（例如麻木）被认为在气候适应方面发挥着重要作用。在这项研究中，我们使用物种范围北缘的两个孤立的 Peromyscus leucopus 谱系来识别显示出强烈环境关联的 SNP，并测试平行进化的证据。我们在每个谱系中发现了临床选择的特征，但平行性的证据有限，只有两个 SNP 显示横断面平行的等位基因频率。这些平行的 SNP 映射到一个参与防止铁依赖性氧化应激 (Fxn) 的基因和一个功能未知但包含叉头相关域 (Fhad1) 的基因。此外，在横断面中，我们发现富含与糖原稳态、突触功能、细胞内 Ca2+ 平衡、H3 组蛋白修饰以及细胞分裂的 G2/M 过渡相关的功能的基因的显着临床模式。我们的结果与最近关于小型哺乳动物气候适应的细胞和分子基础的文献一致，并为进一步研究提供了候选基因组区域。