Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, CA.
Mol Biol Evol. 2019 Jan 1;36(1):155-158. doi: 10.1093/molbev/msy204.
Gene body methylation (gbM) is typically characterized by DNA methylation in the CG context within coding regions and is associated with constitutive genes that have moderate to high expression levels. A recent study discovered the loss of gbM in two plant species (Eutrema salsugineum and Conringia planisiliqua), illustrating that gbM is not necessary for survival and reproduction. The same paper stated there was no detectable effect of gbM loss on gene expression (GE). Here, we reanalyzed the GE data and accounted for experimental variability in expression level estimates. We show that the loss of gbM in E. salsugineum is associated with a small but highly significant decrease in GE relative to the closely related species Arabidospis thaliana. Our results are consistent with various evolutionary analyses that suggest gbM has a function, perhaps as a homeostatic effect on GE.
基因体甲基化（gbM）通常表现为编码区域中 CG 背景下的 DNA 甲基化，与表达水平中等至较高的组成性基因相关。最近的一项研究发现，在两种植物物种（盐穗木和滨藜）中失去了 gbM，表明 gbM 对于生存和繁殖并非必需。同一份论文还指出，gbM 缺失对基因表达（GE）没有可检测到的影响。在这里，我们重新分析了 GE 数据，并考虑了表达水平估计的实验变异性。我们表明，盐穗木中 gbM 的缺失与相对于密切相关的拟南芥物种，GE 有一个小但高度显著的下降有关。我们的结果与各种进化分析一致，表明 gbM 具有功能，可能作为 GE 的一种体内平衡效应。
