Identification Of Individual Identity Of Ningxiang Pigs By DNA Barcode Technique

With the development of modern high-throughput sequencing technology,the barcode technology of DNA deoxyribonucleic acid has been gradually used in the establishment of traceability system for meat products.It is beneficial to protect biodiversity,promote the sustainable use of species resources and provide knowledge and theoretical basis for the development of new products from biological sources.In order to protect local characteristic breeds in Hunan province,this study selected Ningxiang pig,a high quality breed of Ningxiang county,to study the DNA identification of Ningxiang pig's individual identity,which can be used to identify pig individual identity and trace the origin of its products.The results of this study are as follows:1.Primer 1(122),primer 1(242),primer 2(42),primer 3(254)had different genotypic and gene frequencies in two different breeds of Ningxiang pig and Luchuan pig.The distribution of CTTTT in Ningxiang pigs was not significantly different from that in primer 1(122),but there was very little distribution of CC in Luchuan pigs and no TT genotype.In primer 1(242),the gene frequencies of SNP in Ningxiang and Luchuan,two local Chinese pig breeds,also showed extreme distribution.The frequency of genotype was 82.0% in Ningxiang pig and 100% in Luchuan pig.The frequency of genotype was dominated by CC genotype.In primer 2(42),GG played a leading role in the distribution of AGG AA in Ningxiang pigs,and all the GG genotypes were found in Luchuan pigs.The distribution of SNP in Ningxiang pig and Luchuan pig was the same in primer 3(254).2.A total of 6 SNPs were obtained from primer 3.It can be seen from the 3 SNP genotypes of 160,161 and 254 that only three genotypes of AGAGG GGG GGG GGG AaAA were found in 160 and 254 SNP genotypes,and the 2 SNP genotypes in the other 27 samples were only composed of these 3 genotypes.It is suggested that if new SNP are excluded in this population,only AA and GG haplotypes are completely associated with the two SNP types,so one of 160 and 254 can be used for individual identification.And.160,161 SNP can form three genotypes of AATT.It is inferred that there is not a complete correlation between the four haplotypes AATT in these two sites,so both 160 and 161 can be used for individual recognition.3.Based on linkage disequilibrium analysis and heterozygosity screening,25 SNP with 0.10 heterozygosity were selected for identification of Ningxiang pigs and compilation of bar code for traceability of pork products.The genotypes of 30 pig samples from Ningxiang pigs were made into bar codes.The genotypes of the SNP selected in this paper can completely distinguish 30 Ningxiang pigs from the experimental ones.4.Three genotypes were isolated from 30 samples of Ningxiang pigs by using 5 pairs of primers.In theory,there are 7 × 7 × 7 × 7 × 6 × 3 × 6174 combinations of these genotypes,that is,6174 Ningxiang pigs can be identified as individuals.Therefore,the valid SNP that we selected from the sequenced peak map can The corresponding DNA bar code and digital bar code are worked out to satisfy the individual identification of Ningxiang pig in general scale pig farm.Individual identification of other varieties also needs to find their own heterozygosity SNP locus,and then make SNP bar code,in order to improve the accuracy of individual identification.