Epigenomic variation and its relationship with genetic and phenotypic variations in the mouse

一个物种种群内的表型变异可导致物种形成。除了遗传变异外，个体之间的表观遗传调控变异，如DNA甲基化和组蛋白翻译后修饰，也可能是这种表型变异的来源。在本研究中，我们首先建立了一种收集基因组DNA甲基化区域的方法，然后利用下一代测序仪比较了相同物种但不同亚种的小鼠品系之间的DNA甲基化，分别在肝脏和精子中鉴定出大约1500和4000个区域的DNA甲基化水平存在差异。有趣的是，在肝脏中发现的大约一半的区域在精子中也显示出甲基化差异。结合F1杂交分析，结果表明大多数种内表观遗传变异是由于这些区域的顺式序列。

Phenotypic variations within ａ population of ａ species can lead to speciation. Besides genetic variations, variations of epigenetic regulation, such as DNA methylation and histon post-translational modifications, among the individuals could be a source of such phenotypic variation. In this study, we first established ａ method to collect methylated genomic DNA regions, then utilized ａ next generation sequencer to compare DNA methylation between mouse strains of the identical species but different subspecies, which identified about 1500 and 4000 regions showing difference in DNA methylation levels between the strains in liver and sperm, respectively. Interestingly, about half of the regions identified in liver showed methylation difference in sperm as well. Together with a F1 hybrid analysis, the results suggest that majority of intraspecific epigenetic variations are due to cis-sequences of these regions.