Identification of SNPs and Their Effects on Swine Growth and Carcass Traits for Porcine IGFBP-3 Gene

The insulin-like growth factor binding protein-3 (IGFBP-3) was known as a key factor that regulates the effect of insulinlike growth factors (IGF-1 and IGF-2) on pig growth and development. We first identified 38 single nucleotide polymorphisms (SNPs) from a fragment of the IGFBP-3 gene spanning 1 823 bp using the denaturing high-performance liquid chromatography (DHPLC) method and confirmed them by direct sequencing. Among these SNPs, 36 located in introns and the remaining 2 in the 3 prime untranslated region (3'UTR). In addition, 16 PCR-RFLP polymorphisms were identified within these SNPs. Three SNPs were then selected to genotype 272 F2 individuals with PCR-RFLP method and the association of polymorphism with growth and carcass traits were analyzed. The results showed that no significant associations were observed between polymorphisms of A265G and A952G and traits. However, the A2670G significantly related with live body length, loin muscle area, and skin and fat percentage (P < 0.05); highly significantly associated with weight of carcass lean and lean percentage (P < 0.01).