DNA Methylation Difference And Genetic Effect Analysis Between Parents And Offspring Of Pigs Detected By Capillary Electrophoresis

DNA methylation is an important epigenetic modification which plays importantroles in maintaining normal cellular functions, gene imprinting, embryonicdevelopment, and human tumorigenesis, and now it becomes one of the hot points ofresearch. With progresses in study on methylation, sorts of detecting techniques ofmethylation have been developed to meet requirements of various researches.Capillary electrophoresis (CE) is a new separation technique that is one of widelyused and rapidly developing method. It has been successfully used for genetic analysisinstead of conventional slab gel electrophoresis. In this experiment, we associated themethylation-sensitive single-strand conformation polymorphism analysis withlaser-induced fluorescence capillary electrophoresis to set up a new method which isfast separation, high sensitivity, and automated for detection of DNA methylation.In this experiment, three parental lines Large White,Landrace,Meishan and theirhybrids Large White×Landrace,Landrace×Large White,Large White×Meishan,Meishan×Large White were used as the source of DNA samples, a single-strandconformation polymorphism analysis with capillary electrophoresis(SSCP-CE) wasused for the determination of methylation state of IGF2 promoter 2 in muscle tissuesof pigs. At the same time, the significant differences in methylation level ofpromoter between parental lines and their hybrids, based on different hybrid systems,were analyzed. In addition, the association analyses between methylation level ofpromoter and quantity traits were performed. The main results are as follows:1. The SSCP-CE for detecting methylation state of promoter was firstlyestablished in the laboratory.2. These above-mentioned methods based on capillary electrophoresis wereapplied to determine methylation state of IGF2 promoter 2 and promoter of MYF5.3. In muscle tissues, the methylation level in the second promoter of IGF2 gene ofthe hybrids is lower than that of the pure.4. The methylation level of IGF2 promoter2 were compared in different breeds:the difference between Landrace and another breeds is highly significant(p＜0.01).The difference between Meishan and Large White xMeishan is significant(p＜0.05).5. The SAS statistics software was used to analyze the relationship between themethylation level of IGF2 promoter2 and economic traits: in the 65 samples ofLarge White, Landrace and their hybrids, the methylation level of IGF2 promoter2affected a series of backfat thickness,loin eye height(LEH),loin eye area(LEA), fat meat percentage(FMP) and lean meat percentage(LMP) significantly(p＜0.05) orhigh significantly(p＜0.01). There was no significant difference between themeythlation level of IGF2 promoter2 and meat traits.6. In the 120 samples of Meishan and Large WhitexMeishan,Meishan×Large White hybrids, the methylation level of IGF2 promoter2 affectedloin eye height(LEH),loin eye area(LEA) significantly(p＜0.05) or highsignificantly(p＜0.01). In the meat traits, the methylation level of IGF2 promoter2affected water moisture of m.longissimus Dorsi(LD WM) significantly(p＜0.05) andaffected meat pH of m.longissimus Dorsi(LD pH),drip loss rate of m.longissimusDorsi(LD DLR),water holding capacity of m.longissimus Dorsi(LD WHC),meatcolor walue of m. longissimus Dorsi(LD MCV1) high significantly(p＜0.01).