Differential DNA Methylation Analyses Between Bos Indicus And Bos Taurus By Whole-genome Bisulfite Sequencing

Cattle consists of two main groups,namely Bos indicus and Bos taurus which provides abundant phenotype diversity and genetic diversity.It is ideal resources for studying the molecular genetic basis in the phenotype among livestock.As one of the epigenetic modification methods,and also a bridge between genotype and phenotype,DNA methylation plays a crucial role in various biological metabolic processes.At present,the majority of studies on DNA methylation focus on model organisms like human cell lines,mice,zebrafish and so on.However,few studies on DNA methylation have been done on domestic livestock.In the present study,four livers of B.taurus and B.indicus was sequenced by WGBS to explore the methylation patterns of cattle,establish cattle genome methylation profiles and find the differentially methylated genes or regions.After sequence alignment and bioinformatic tools are used,our result shows that about 15 million cytosine were methylated in a sample,and the mainly methylation patterns is CG context that counted 95%,which is much higher than CHH and CHG context.As well gene and introns both are the functional elements with the highest level of methylation.The methylation patterns of cattle are described at genome scale and chromosome scale respectively and CG context with the highest methylation level is observed.In the present study,448 distinct differentially methylated regions(DMRs)we identified,273 differentially methylated genes were significantly enriched into 40 GO terms.KEGG analysis shows that DMR related genes were enriched into 12 pathways like pathway in cancer and purine metabolism.In this study,DMRs related genes’function involved in disease and immune were identified,which is important in the epigenetic research of the differences in phenotypes and disease resistance between B.taurus and B.indicus.