The Polymorphism Of Ob Gene And Its Correlation With Litter Performance And Early Growth Performance In Pig

This thesis gave a study on the polymorphism of ob gene in erhualian, xiang pig, Large White, Duroc, Landrace, Pietran and Landrace X erhualian crossbreeds , by means of Bi-PASA. Variance analysis showed the correlation of genotypes with litter size and growth performance ,and the polymorphism of OB gene locus respectively. Our purpose is to find the correlation of ob gene with reproduction and growth performance and identify a molecular genetic markers for pig breeding to lay the foundation for Marker-assisted selection. The results showed: 1. Ob gene was found to have 2 alleles (G and T) and 3 genotypes (GIG, Gil?and TilT) by Bi-PASA. 2.There was abundant polymorphism of ob gene in every breeds, and there was significant difference in gene frequency among different breeds, with high T allele frequency in domestic breeds and high U in foreign. 3. Variance analysis revealed that the Bi-PASA markers at ob gene had a high linkage with litter size. The litter size of GIG genotype was by 2.3 and 2.1 lower than G/T type and T/T type, respectively. 4. Variance analysis revealed that ob gene had a high linkage with early growth of pig. The 20 days and 35 days weight of G/T types ware 0.5 1kg and 1.0kg higher than those of T/T types, respectively.