Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, 19104, USA.
School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Sci Rep. 2016 Nov 16;6:37110. doi: 10.1038/srep37110.
Epigenetic inheritance plays an important role in mediating alternative phenotype in highly social species. In order to gain a greater understanding of epigenetic effects in societies, we investigated DNA methylation in the termite Zootermopsis nevadensis. Termites are the most ancient social insects, and developmentally distinct from highly-studied, hymenopteran social insects. We used replicated bisulfite-sequencing to investigate patterns of DNA methylation in both sexes and among castes of Z. nevadensis. We discovered that Z. nevadensis displayed some of the highest levels of DNA methylation found in insects. We also found strong differences in methylation between castes. Methylated genes tended to be uniformly and highly expressed demonstrating the antiquity of associations between intragenic methylation and gene expression. Differentially methylated genes were more likely to be alternatively spliced than not differentially methylated genes, and possessed considerable enrichment for development-associated functions. We further observed strong overrepresentation of multiple transcription factor binding sites and miRNA profiles associated with differential methylation, providing new insights into the possible function of DNA methylation. Overall, our results show that DNA methylation is widespread and associated with caste differences in termites. More generally, this study provides insights into the function of DNA methylation and the success of insect societies.
表观遗传继承在介导高度社会化物种的替代表型方面起着重要作用。为了更深入地了解社会中的表观遗传效应，我们研究了白蚁 Zootermopsis nevadensis 中的 DNA 甲基化。白蚁是最古老的社会性昆虫，在发育上与高度研究的膜翅目社会性昆虫不同。我们使用复制的亚硫酸氢盐测序来研究 Z. nevadensis 两性和不同阶层中的 DNA 甲基化模式。我们发现 Z. nevadensis 显示出昆虫中发现的最高水平的 DNA 甲基化之一。我们还发现了不同阶层之间甲基化的强烈差异。甲基化基因往往均匀且高度表达，表明基因内甲基化与基因表达之间的关联具有古老性。与未发生差异甲基化的基因相比，差异甲基化基因更有可能发生选择性剪接，并且具有丰富的与发育相关的功能。我们进一步观察到与差异甲基化相关的多个转录因子结合位点和 miRNA 谱的强烈过表达，为 DNA 甲基化的可能功能提供了新的见解。总的来说，我们的研究结果表明 DNA 甲基化在白蚁中广泛存在，并与阶层差异有关。更普遍地说，这项研究提供了对 DNA 甲基化功能和昆虫社会成功的深入了解。
