| Blood,as a connective tissue that communicates between organs,aggregates the metabolic and transcriptional variations of the entire system,is the key to ensuring flexible communication between system functions,so blood has the potential to systematically analyze biological mechanisms.Allele-specific expression(ASE)is a newly discovered genetic phenomenon,which two alleles at the same locus are transcribed,but the expression level of the two alleles is significantly different,and usually the allele with higher expression shows preferentially expressed.Studies have shown that ASE is closely related to production,immunity and other aspects.The study of ASE in blood is helpflil to understand the potential influence of the allelic expression on the production performance of dairy cows and provide a theoretical basis for improving the performance of dairy cows.The objective of this study is reveal the ASE of blood among different groups of dairy cows by using RNA-Seq technology,including high and low-yield cows,lactationg and dry cows,and calves before and after weaning.The main results are as follows:The comparison of the allele-specific expression of whole blood in high and low-yield dairy cows showed that there were 698 ASE specific genes in the high yield group and 377 specific ASE genes in the low yield group.Gene function enrichment analysis found that some genes in the high yield group were associated with milk performance traits,while most of the ASE genes in low-yield groups were significantly enriched in immune and disease-related pathways.The comparison of allele-specific expression of whole blood in lactating and the dry cows showed that the dry period group had 442 specific ASE genes and lactating groups had 564 specific ASE genes.PIM1 in the lactation group was associated with protein modification;COQ2 was involved in the synthesis of triacylglycerol(TAG);IL1B and BOLA-DQA1 were involved in the immune response,and enrichment analysis revealed that these genes were mainly involved in the energy metabolism pathway.The ASE genes in low-yield group were enriched in pathways such as cell aging,apoptosis,and cell division.The comparison of the allele-specific expression of whole blood of calves before and after weaning,it was found that 690 specific ASE genes were identified in calves before weaning and 784 specific ASE genes were in calves after weaning.The ASE genes weaned calves were not found to be enriched in immune and inflammatory pathways related to weaning stress.The ASE genes before and after gradual weaning were enriched in the pathways related to cell processing,cell adhesion,cell division and proliferation,and liver tissue development.In summary,ASE is widespread in cows,which reflects the fact that the alleles changes its expression in different physiological states of cows.This can provide theory basis for the selection and identification of genes associated with milk traits in dairy cows. |
