Comparative Genome-wide DNA Methylation Analysis Of Spleen Tissues Between Yunnan Humped Cattle And Hostein Cattle

Yunnan humped cattle has typical characteristics of beef cattle,while Holstein cattle is a world famous cow breed.These two kinds of domestic cattle are representative breed of Bos indicus type and Bos Taurus type respectively,and there are obvious differences in appearance characteristics,production performance,environmental adaptation and disease resistance.Epigenomics studies the epigenetic modification on genome,it plays a crucial role in embryos development,expression of gene,cancer development and other biological processes.DNA methylation is the most intensively studied among epigenetic modifications,and it is a crucial epigenetic modification in gene expression,growthing and development,cell proliferation,cell differentiation and cancer.Spleen is a good material for the study of immunity and growth,in this work,we sequence and comparative analysis genome-wide methylation of spleen between two type cattle by whole genome bisulfite sequencing(WGBS),we aim to understand the DNA methylation patterns in the spleen tissues of the two cattle breed;explore the differentially methylated regions(DMR)and the function of DMR related genes.This study will be valuable for epigenetic molecular marker screening of the differences in production traits and disease resistance between the two breeds.After sequence alignment and bioinformatic tools are used,PBT57、PBT47、PBT24、PBI33、PBI52 and PBI15 were extracted into approximately 15、17、14、13、13 and 11 million methylated cytosines,respectively.And the mainly methylation patterns is CG context which counted more than 95.5% in each sample.The methylation level in CG context is much higher than CHG and CHH context,The DNA methylation level of CHG and CHH context are very low(close to 0).5’UTR has the lowest methylation level among functional elements,and the methylation level of transcription element shows that the first exon was lower.The methylation patterns of two breeds are described at genome scale respectively and CG context with higher methylation level is observed.Overall,9497 differentially methylated regions(DMR)were identified and 2718 genes which are related to differentially methylated region were annotated,and most of DMRs were annotated in exon.These genes were significantly enriched into 533 GO terms,among them 351 in Biological Process,98 in Cellular Component and 84 in Molecular Function.KEGG analysis shows that DMR related genes were significantly enriched into 37 pathway like calcium signaling pathway,cell adhesion molecules(CAMs),pathway in cancer and purine metabolism.These genes involved in the production performance and immune response of Yunnan humped cattle and Holstein cattle.Our work is important in epigenomics researcher of the differences in phenotypes,production performance and disease resistance between Yunnan humped cattle and Holstein cattle.Our results will be valuable for future genomic and epigenomic studies of two breeds and epigenetic molecular marker screening of the differences in production traits and disease resistance between the two breeds.