Correlation analysis of DKK1 gene polymorphism and growth traits of F₃ generation Xiangsu hybrid pigs

【Objective】Single nucleotide polymorphisms(SNPs)of the Dickkopf-1(DKKI)gene of the F₃ generation Xiangsu hybrid pigs were screened out,and the correlation between the gene polymorphism and growth traits was analyzed,in order to cultivate a new line of Xiangsu hybrid pigs,so as to lay a foundation for in-depth study on the biological function of DKK1 gene.【Method】SNPs of DKK1 gene in 164 F₃generation Xiangsu hybrid pig populations were identified by DNA mixed pool sequencing.Gene frequency,genotype frequency,genetic homozygosity(Ho),expected heterozygosity(He),effective allele number(Ne)and polymorphic information content(PIC)of different genotypes were calculated by Excel 2017.Chi square(χ²) test was used to analyze whether the genotypes were in Hardy-Weinberg equilibrium,then the association between SNPs and growth traits in F₃ Xiangsu hybrid pigs was analyzed based on it.【Result】Six SNPs were found in Exon-3,4 region of DKK1 gene of F₃ Xiangsu hybrid pigs,which were A2010T,G2012C,C2014T,A2040C,C2042A and G2044C respectively.Ho of the six SNPs was higher than that of He.The PIC of the five SNPs,A2010T,G2012C,A2040C,C2042A and G2044C was at the moderate polymorphism level,while the pic of C2014T was at the low polymorphism level.χ² test results showed that only C2042A locus was in Hardy-Weinberg extreme disequilibrium state(P<0.01),and the other five SNPs loci(A2010T,G2012C,C2014T,A2040C and G2044C)were in Hardy-Weinberg equilibrium state(P>0.05).The results of association analysis showed that different genotypes of DKK1 gene A2010T,G2012C,C2014T,A2040C and G2044C in F₃ generation Xiangsu hybrid pigs showed significant differences in body height,chest circumference,tube circumference,chest depth or leg and hip circumference(P<0.05)or extremely significant(P<0.01).【Conclusion】Different genotypes at A2010T,G2012C,C2014T,A2040C and G2044C of DKK1 gene in F₃ Xiangsu hybrid pigs are significantly or extremely significantly correlated with body height,chest circumference,tube circumference,chest depth orleg and hip circumference,which can be used as the main candidate gene or molecular markers closely linked with the main genes for breeding new lines.