Polymorphisms Of MC1R、ASIP、TYR、TYRP1、SLC45A2 Gene And Their Association With Coat Color In Pigs

The coat color of pig is one of the most important characteristics of variety.As a genetic marker,it can be used to identify the purity and phylogeny of the pig,to identify the hybrids,and to evaluate the quality of the products.Studies have shown that the phenotypic difference of pigmentation is mainly determined by the type,proportion and distribution of pigments in hair.In this study,Qingping pigs and their hybrid offspring with French Large White pigs were selected as the research objects.5 genes related to melanin synthesis（MC1R,ASIP,TYR,TYRP1 and SLC45A2 genes）were selected as candidate genes.SNPs was screened from the GWAS sequencing results of 100 Qingping sows in the early stage of the laboratory,and 5 of the progenies were identified by target acquisition and sequencing.Genotypes of SNPs locus of pigmentation-related genes were studied to investigate their single nucleotide polymorphisms.The main results are as follows:1.In Qingping pig MC1R gene CDs region,7 SNPs locus were screened,the ID of four missense mutations are rs326921593,rs705222433,rs45434630 and rs45434629respectively,the ID of three synonymous mutations are rs327940565,rs45435031 and rs345201947 respectively.The sequencing results showed that the black phenotype of Qingping pigs was controlled by the E^D1 allele and belonged to the dominant black coat color system,which was consistent with the results of other Chinese black pigs.2.In the CDs region of Qingping pigs ASIP gene,1 nonsynonymous SNP were screened and the ID is rs695545599.The rs695545599 loci of 7 different hair colors individuals in the F₂ generation of the Large White×Qingqing（Daqing）were genotyped by chi square test.The results showed that there was no significant difference in the distribution of genotypes in the 7 coat color populations（P>0.05）.3.Qingping pigs TYR gene CDs screened 8 SNPs locus,1 of which were nonsynonymous SNP,this is a new mutation,named as g.22603899 G>C.Genotyping of g.22603899 G>C loci in seven different coat color individuals of Daqing hybrid F₂generation was carried out.Chi-square test results showed that the distribution of each genotype of this loci was significantly different among seven coat color populations（P<0.05）,indicating that the mutation may be related to the variation of coat color of pigs,but further studies are needed to prove that the mutation is related to the variation of coat colors of pigs.4.Qingping pigs TYRP1 gene CDs region screened 7 SNPs locus,3 of which were nonsynonymous SNPs,ID are rs80932060,rs80930111 and rs328212230 respectively.Three locus of 7 different coat color individuals in Daqing hybrid F₂ generation were genotyped.Chi-square test results showed that there was no significant difference in the distribution of the genotypes of these three locus among 7 different coat color populations（P>0.05）,indicating that the three locus were not related to the variation of pig coat colors.5.11 SNPs locus were screened in the CDs region of Qingping pigs SLC45A2 gene,1 of which were nonsynonymous SNP,ID is rs318960545.Genotyping of rs318960545loci in 7 different coat color individuals of Daqing hybrid F₂ generation was carried out.Chi-square test results showed that there was no significant difference in the distribution of each genotype of the loci among the seven coat color populations（P>0.05）,indicating that the loci was not related to the variation of pig coat colors.