Epigenetic modification plays a critical role in establishing and maintaining cell differentiation, embryo development, tumorigenesis and many complex diseases. However, little is known about the epigenetic regulatory mechanisms for milk production in dairy cattle. Here, we conducted an epigenome-wide study, together with gene expression profiles to identify important epigenetic candidate genes related to the milk production traits in dairy cattle. Whole-genome bisulphite sequencing and RNA sequencing were employed to detect differentially methylated genes (DMG) and differentially expressed genes (DEG) in blood samples in dry period and lactation period between two groups of cows with extremely high and low milk production performance. A total of 10,877 and 6,617 differentially methylated regions were identified between the two groups in the two periods, which corresponded to 3,601 and 2,802 DMGs, respectively. Furthermore, 156 DEGs overlap with DMGs in comparison of the two groups, and 131 DEGs overlap with DMGs in comparison of the two periods. By integrating methylome, transcriptome and GWAS data, some potential candidate genes for milk production traits in dairy cattle were suggested, such as DOCK1, PTK2 and PIK3R1. Our studies may contribute to a better understanding of epigenetic modification on milk production traits of dairy cattle.

中文翻译：

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全基因组 DNA 甲基化和基因表达谱的综合分析揭示了与奶牛产奶性状相关的重要表观遗传基因

表观遗传修饰在建立和维持细胞分化、胚胎发育、肿瘤发生和许多复杂疾病中起着关键作用。然而，对奶牛产奶的表观遗传调控机制知之甚少。在这里，我们进行了表观基因组范围的研究，连同基因表达谱，以确定与奶牛产奶性状相关的重要表观遗传候选基因。采用全基因组亚硫酸氢盐测序和RNA测序检测两组产奶性能极高和极低的奶牛在干奶期和泌乳期血样中的差异甲基化基因（DMG）和差异表达基因（DEG）。一共10877和6，在两个时期的两组之间鉴定出 617 个差异甲基化区域，分别对应于 3,601 和 2,802 个 DMG。此外，在两组比较中，156°与DMGs重叠，在两个时期比较中，131°与DMGs重叠。通过整合甲基化组、转录组和 GWAS 数据，提出了奶牛产奶性状的一些潜在候选基因，例如DOCK1、PTK2和PIK3R1。我们的研究可能有助于更好地了解表观遗传修饰对奶牛产奶性状的影响。