Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, USA.
Sci Rep. 2023 Sep 9;13(1):14901. doi: 10.1038/s41598-023-41896-7.
Unraveling molecular mechanisms of adaptation to complex environments is crucial to understanding tolerance of abiotic pressures and responses to climatic change. Epigenetic variation is increasingly recognized as a mechanism that can facilitate rapid responses to changing environmental cues. To investigate variation in genetic and epigenetic diversity at spatial and thermal extremes, we use whole genome and methylome sequencing to generate a high-resolution map of DNA methylation in the bumble bee Bombus vosnesenskii. We sample two populations representing spatial and environmental range extremes (a warm southern low-elevation site and a cold northern high-elevation site) previously shown to exhibit differences in thermal tolerance and determine positions in the genome that are consistently and variably methylated across samples. Bisulfite sequencing reveals methylation characteristics similar to other arthropods, with low global CpG methylation but high methylation concentrated in gene bodies and in genome regions with low nucleotide diversity. Differentially methylated sites (n = 2066) were largely hypomethylated in the northern high-elevation population but not related to local sequence differentiation. The concentration of methylated and differentially methylated sites in exons and putative promoter regions suggests a possible role in gene regulation, and this high-resolution analysis of intraspecific epigenetic variation in wild Bombus suggests that the function of methylation in niche adaptation would be worth further investigation.
揭示适应复杂环境的分子机制对于理解生物对非生物压力的耐受和对气候变化的响应至关重要。越来越多的人认识到，表观遗传变异是一种可以促进对环境变化的快速反应的机制。为了研究空间和温度极端条件下遗传和表观遗传多样性的变化，我们使用全基因组和甲基组测序技术，生成了熊蜂 Bombus vosnesenskii 的 DNA 甲基化高分辨率图谱。我们对两个种群进行了采样，这两个种群代表了空间和环境范围的极端情况（一个温暖的南部低海拔地点和一个寒冷的北部高海拔地点），以前的研究表明这两个种群在耐热性方面存在差异，并确定了在整个样本中一致和可变甲基化的基因组位置。亚硫酸氢盐测序揭示了与其他节肢动物相似的甲基化特征，即全局 CpG 甲基化水平较低，但高甲基化集中在基因体和核苷酸多样性较低的基因组区域。差异甲基化位点（n=2066）在北部高海拔种群中主要呈低甲基化状态，但与局部序列分化无关。外显子和推定启动子区域中甲基化和差异甲基化位点的浓度表明其可能在基因调控中发挥作用，对野生熊蜂种内表观遗传变异的这种高分辨率分析表明，甲基化在生态位适应中的功能值得进一步研究。
