Detection Of HBEGF、KPNA7、FOXA2 And PTGS2 Gene SNPs And Association With Reproductive Traits In Pigs

The economic benefits of pig farms were largely determined by the reproductive performance of sows,while as a quantitative trait,reproductive traits are controlled by minor-polygene and has their low heritability.It is difficult to make significant progress in a short time using traditional breeding techniques.At present,domestic and foreign breeding researchers combine marker-assisted selection(MAS)with conventional breeding methods to promote the genetic improvement process of pig reproductive traits Therefore,identification of candidate genes or molecular markers affecting reproductive traits will provide important theoretical basis for pig molecular breeding.In this study,we selected four candidate genes HBEGF,KPNA7,FOXA2 and PTGS2 based on GWAS and gene function,detected SNP using PCR-RFLP and Sequenom mass spectrometry,and investigated their association with reproductive traits in Large White pigs.The main results were as follows:(1)In France Large White pigs,three new SNP,rs81218760,rs81218761 and rs333992579,were identified in intron 1 and 3 of HBEGF gene.In the France Large White sows,individuals with genotype AC at rs81218760 site had significantly higher litter weight at birth than those with genotype AA(p<0.05),and genotype CC individuals had significantly lower number of weak piglet than those with genotype AC and AA(P<0.05).Individuals with genotype CC of rs81218761 had significantly lower number of weak piglet than that of genotype TT(P<0.05)in first parity and multi parity.Individuals with genotype TC of rs333992579 had significantly higher litter weight at birth than genotype TT(p<0.05)in first parity and multi parity,in addition,individuals with genotype TC had significantly higher healthy litter than genotype TT(p<0.05),and had significantly lower number of weak piglet than genotype TT(P<0.05)in multi parity.(2)Six new SNP including rs81308652,rs321312903,rs327848277,rs334590006,rs336259402 and rs339249916 were identified in exon 1,exon 3,intron 1 and 3 of KPNA7 gene in France Large White pigs.In the France Large White sows,individuals with genotype CT of rs81308652 had significantly higher total number born than genotype TT(p<0.05)in first parity,and individuals with genotype TT had significantly lower number of weak piglet than genotype CC(P<0.05)in multi parity.Individuals with genotype GG of rs327848277 had significantly higher litter weight at birth and total number born than genotype GT(p<0.05)in first parity,and individuals with genotype GG had significantly lower number of weak piglet than genotype GT(P<0.05)in multi parity.There was no significant association of the polymorphism of other four loci with reproductive traits in France Large White pigs.(3)A novel SNP of rs328630446 located in 3 ’UTR region FOXA2 gene was detected in France Large White pigs.Individuals with genotype GG and CG of rs328630446 had significantly lower number of weak piglet than genotype CC(P<0.05).(4)In American and France Large White pigs,a novel SNP,rs322152513 was detected in exon 9 of PTGS2 gene.In American Large White pigs,individuals with genotype AA of rs322152513 had significantly lower number of weak piglet than genotype AG(P<0.05)in first parity,and individuals with genotype AA had significantly higher litter weight at birth than genotype AG(P<0.05)in multi parity.However,there was no significant association of the polymorphism of PTGS2 gene with reproductive traits in France Large White pigs.In conclusion,this study showed that there are significant association of identified SNPs located in the HBEGF,KPNA7,FOXA2 and PTGS2 genes with pig reproductive traits,and provided a theoretical basis for genetic improvement of pig reproductive traits.