Polymorphism Of IGFBP2 And RFRP Genes And Their Association With Reproductive Traits In Large White Sows

In order to reveal the association between IGFBP2 and RFRP genes and reproductive traits in large white sows,this study used PCR product direct sequencing to detect the polymorphism of IGFBP2 and RFRP genes in 403 large white sows.The least squares analysis model was used to analyze the association between the genotypes and haplotype combinations of each SNP locus of the two genes and seven reproductive trait indicators of large white sows.The main results were as follows:(1)A total of four SNPs were detected in the IGFBP2 gene,all of which were located in the 3’-UTR region(1100＿1101ins C,C1287 T,1321ins GTG,and 1361 ins A).Among them,1100＿1101 ins C and 1321 ins GTG loci were only homozygous insertion mutations.A total of 13 SNPs were detected in the RFRP gene,of which 12 SNPs were located in exon 2(G289A,C294 T,A330T/C,G331 A,T349G,C357 T,G358A,C410 T,C411G,T447 A,T457C,and G473A),and 1 SNP was located in exon 3(T588A),including 5synonymous mutations and 7 missense mutations.(2)The C1287 T and 1361 insA loci of the IGFBP2 gene are both moderate polymorphism(PIC ranging from 0.3680 to 0.3657),and their genetic diversity(H ranging from 0.4862 to 0.4817)is relatively rich,but there are not in a Hardy-Weinberg equilibrium state(P <0.01).Except for the A330T/C locus,all other loci of the RFRP gene were in a Hardy-Weinberg equilibrium state(P >0.05).Among them,G289 A,C357T,C294 T,G358A,C410 T,C411G,T447 A,T457C,and T588 A loci exhibit moderate polymorphism(PIC ranging from 0.2911 to 0.3730),and genetic diversity is also relatively rich(H ranging from 0.3537 to 0.4960).The A330T/C,G331 A,T349G,and G473 A loci exhibit low degree polymorphism(PIC ranging from 0.04 to 0.1756),and the genetic diversity of G331 A,T349G,and G473 A loci is low(H ranging from 0.1926 to 0.1945).(3)There was no significant difference between different genotypes of IGFBP2 gene at C1287 T and 1361 ins A loci and the gestation period,number born alive,number of dead births,total number born,litter weight at birth,litter weight at weaning,and litter weight at21 day in large white sows(P >0.05).(4)There were significant differences between different genotypes at the A330T/C,T457 C,and T588 A loci of the RFRP gene and the total number born,litter weight at birth,and litter weight at 21 day of large white sows(P <0.05).And there were significant differences between different haplotype combinations of RFRP gene and the gestation period,number born alive,number of dead births,litter weight at birth,litter weight at weaning,and litter weight at 21 day of large white sows(P <0.05 or P <0.01).The results preliminarily confirmed that there was no significant association between the IGFBP2 gene and reproductive traits of large white sows,while RFRP gene was significantly associated with reproductive traits such as gestation period,number born alive,number of dead births,litter weight at birth,litter weight at weaning,and litter weight at 21 day of large white sows.