Genomic DNA Methylation Analysis Of Muscle Tissue Among Three Local Chicken Breeds

DNA methylation is catalyzed by DNA methyltransferases (Mtases) which transfer a methylgroup from S-adenosine-L-methionine to the5th carbon of cytosine. DNA methylation plays acrucial role in many biological processes, including gene expression regulation, X chromosomeinactivation, genomic imprinting, cell differentiation, chromatin modification, cancer developmentand embryo development. The main function of DNA methylation, which mostly occurs at CpGislands, is to inhibit gene expression. Significant differences in methylation levels have been foundin different tissues and in different individuals within the same organization. Many studies haveshown that different methylation levels may be associated with tissue-specific transcription orcertain traits and can play a crucial role in normal differentiation, development and some traits.TheMeat quality traits are complicated traits traits are controlled by many genes, some of which mayplay a major role. Changes in the methylation levels of certain genes controlling meat quality traitswill inevitably affect their expression levels, thereby affecting meat quality traits.DNA methylation levels were affected by breed, sex, age, environment, feeding andmanagement, and there are differences in the temporal and spatial expression. In the present study,we used the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP)method to investigate the differences of genome DNA methylation levels in pectoral muscletissues of male Wenshang Barred chicken, a total of19,795fragments were obtained including8935unmethylated bands,5668hemimethylated bands and5192fully methylated bands.Hemimethylation ratio of pectoral muscle was higher than that of other tissues(P<0.05), fullymethylation ratio of lung was significantly higher than that of other tissues(P<0.01), andmethylation ratios of pectoral muscle and lung were higher than that of other tissues(P<0.05).We also used the F-MSAP which we founded to investigate the DNA methylation leveldifferences in pectoral muscle tissues and their relationships with meat quality traits of male Wenshang Barred chicken, Xianju chicken and Huaibei Partridge chicken. There was nosignificant different of hemimethylated ratio among three breeds(P>0.05); The fully methylationratio of Xianju chicken was significantly higher than that of Huaibei Partridge chicken, andHuaibei Partridge chicken was significantly higher than that of Wenshang Barred chicken(P<0.01);For the methylation ratio, Xianju chicken was significantly higher than that of Huaibei Partridgechicken and Wenshang Barred chicken, but there was no significant different between WenshangBarred chicken and Huaibei Partridge chicken. The correlation analysis between the methylationlevels and the meat quality traits were also done, The results showed that different methylationlevels were highly significant correlations with muscle fiber density and shear force in WenshangBarred chicken (P<0.01), and for Xianju chicken different methylation levels were highlysignificant correlations with muscle fiber density and drip loss (P<0.01), but for Huaibei Partridgechicken methylation levels were significant correlations with drip loss(P<0.05). However, nosignificant correlations were found with other traits in three breeds (P>0.05).The association of the specific methylation FABP4with the meat quality traits were detected,The results showed that the levels of FABP4mRNA were highly significant correlations withshear force of pectoral muscle in Wenshang Barred chicken(P<0.05), However, no significantcorrelations were found with other meat quality traits (P>0.05).