Heredity ( IF 3.1 ) Pub Date : 2023-01-19 , DOI: 10.1038/s41437-023-00591-z
H. Marshall , M. T. Nicholas , J. S. van Zweden , F. Wäckers , L. Ross , T. Wenseleers , E. B. Mallon
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Social insects display extreme phenotypic differences between sexes and castes even though the underlying genome can be almost identical. Epigenetic processes have been proposed as a possible mechanism for mediating these phenotypic differences. Using whole genome bisulfite sequencing of queens, males, and reproductive female workers we have characterised the sex- and caste-specific methylome of the bumblebee Bombus terrestris. We have identified a potential role for DNA methylation in histone modification processes which may influence sex and caste phenotypic differences. We also find differentially methylated genes generally show low levels of DNA methylation which may suggest a separate function for lowly methylated genes in mediating transcriptional plasticity, unlike highly methylated genes which are usually involved in housekeeping functions. We also examined the relationship between the underlying genome and the methylome using whole genome re-sequencing of the same queens and males. We find DNA methylation is enriched at zero-fold degenerate sites. We suggest DNA methylation may be acting as a targeted mutagen at these sites, providing substrate for selection via non-synonymous changes in the underlying genome. However, we did not see any relationship between DNA methylation and rates of positive selection in our samples. In order to fully assess a possible role for DNA methylation in adaptive processes a specifically designed study using natural population data is needed.
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DNA 甲基化与一种大黄蜂的密码子简并性有关
社会性昆虫在性别和种姓之间表现出极端的表型差异,即使潜在的基因组几乎相同。表观遗传过程已被提议作为调节这些表型差异的可能机制。使用蜂后、雄性和生殖雌性工蜂的全基因组亚硫酸氢盐测序,我们已经表征了大黄蜂Bombus terrestris的性别和种姓特异性甲基化组. 我们已经确定了 DNA 甲基化在组蛋白修饰过程中的潜在作用,这可能会影响性别和种姓表型差异。我们还发现差异甲基化基因通常表现出低水平的 DNA 甲基化,这可能表明低甲基化基因在介导转录可塑性方面具有独立的功能,这与通常参与管家功能的高甲基化基因不同。我们还使用相同蜂王和雄性的全基因组重测序检查了基础基因组和甲基化组之间的关系。我们发现 DNA 甲基化在零倍简并位点富集。我们认为 DNA 甲基化可能在这些位点充当靶向诱变剂,通过基础基因组中的非同义变化为选择提供底物。然而,在我们的样本中,我们没有发现 DNA 甲基化与阳性选择率之间有任何关系。为了充分评估 DNA 甲基化在适应过程中的可能作用,需要使用自然种群数据进行专门设计的研究。