Difference Of Gene Methylation Rate Between Farmed And Wild Animal And Its Implication For Origin Discrimination Of Skeletal Muscle

Commercial farming of endangered wildlife has potential to reduce poaching pressure on wild populations.However,poached products might be laundered under the guise of a farmed origin.A method to discriminate farmed products from wild is therefore essential for effective law enforcement.The source of meat(skeletal muscle)which is a major wildlife product is difficult to determine.Therefore,in this study,method to determine the source of skeletal muscle were investigated by analyzing DNA methylation level.First,a single gene methylation level of mink,as a representative of warm-blooded animal,was analyzed.The methylation rate of the ?-actinin-3(ACTN3)gene promoter in gluteus maximus tissues of feral(n=21)and farmed(n=21)American mink(Neovison vison)were analyzed by using mass-spectrography.Results showed that the accuracy of assignment range from 59.5% to 76.2% on each of five CpG sites/site groups.Joint assignment accuracy of the five CpG sites/site groups achieved 83.3%,90.5% for the farmed group and 76.2% for the wild group.These results indicated that methylation of some genes differ in skeletal muscle of farmed animals and wild animals,and this difference could be used to effectively discriminate meat from farmed and wild animals.Secondly,the king ratsnake(Elaphe carinata)were used as whole genome methylation level of cold-blooded animal was analyzed using king ratsnake(Elaphe carinata)as representative(or model).Genome DNA of Musculus spinalis dorsi from wild(n=5)and farmed(n=5)king ratsnakes were analyzed by using Methyl RAD technique.The results showed that there were differences in DNA methylation at 236134 CCGG sequences and 58451 CCWGG sequences between two groups.However,the average level of whole genome DNA methylation at CCGG sequences was 4.147 in farmed group,and was 4.147 in wild group.The average level of whole genome DNA methylation at CCWGG was 17.105 in farmed group,and 17.106 in wild group.The difference in mean methylation level was extremely small between two groups,and could not be used for discrimination.Therefore,from the tested sequences,sequences,with intergroup difference of methylation greater than 20 and intragroup difference less than 15%,and matching with the re-sequencing results,should be screened and subject to subsequent large sample size analysis to verify the practicability of discriminating skeletal muscle source by methylation difference.