Genome-wide DNA Methylation Patterns in Daphnia magna Reveal Targeting to 5’ Exons

Daphnia magna is a widely used model organism in ecological and evolutionary studies. DNA methylation in D. magna can influence development and adaptation to changing environments. Previous studies have demonstrated that D. magna is generally hypomethylated. In this study we confirmed these observations using whole genome bisulfite sequencing (WGBS). In line with previous studies we observe that DNA methylation is elevated in the first exons downstream of the transcription start sites (TSS). Moreover, these exons are hypermethylated compared to adjacent introns. In contrast to prior studies in Daphnia, we found no significant changes in DNA methylation with age. These observations extend our understanding of the epigenetic landscape in D. magna, and motivate further exploration of epigenetic regulation in this organism and its response to environmental factors. Bisulfite sequencing of whole genome WT Daphnia magna from 3 age groups (18 samples)

大型溞（Daphnia magna）是生态学与进化研究中广泛应用的模式生物。大型溞的DNA甲基化可影响其发育及对环境变化的适应性。既往研究表明，大型溞整体呈现低甲基化特征。本研究通过全基因组亚硫酸氢盐测序（whole genome bisulfite sequencing, WGBS）验证了上述结论。与既往研究一致，我们观察到转录起始位点（transcription start sites, TSS）下游的首个外显子区域DNA甲基化水平升高。此外，相较于相邻内含子区域，此类外显子呈现高甲基化状态。与以往针对大型溞的研究不同，我们未发现DNA甲基化水平随年龄出现显著变化。上述发现拓展了我们对大型溞表观遗传图谱的认知，为进一步探索该物种的表观遗传调控机制及其对环境因素的响应提供了研究方向。本研究对3个年龄组的野生型（wild type, WT）大型溞开展全基因组亚硫酸氢盐测序，共获得18份样本。