The polymorphism detection of IGF2 gene and correlation analysis with growth traits
The polymorphism at intro 3 of IGF2 gene in Landrace and Yorkshire was detected by PCR-SNaPshot in 395 pig ear skins of nucleus group, and the correlation between the genotypes of IGF2 gene and growth traits was analyzed. The result indicated that there were three kinds of genotypes in the two swine populations. The three kinds of genotypes frequencies of Yorkshire pigs were AA > GA > CG, and those of Landrace were GA > AA > GG. The A allele frequencies of Yorkshire and Landrace pigs were 0.710 and 0.541 respectively, G allele frequencies were 0.290 and 0.459 respectively. Correlation analysis result showed that the AA genotype had faster growth rate than GA and GG genotypes. The allele A had a positive effect on growth rate, and led to backfat thickness. The living mean BFT to 100 kg and the estimated breeding value (EBV) of the living mean BFT to 100 kg of pig with the three kinds of genotypes was as follows; GG > GA > AA. Therefore, in the selection process of pig breeding, the individual with allele A should be selected generation-by-generation for raising the growth rate, reducing the backfat thickness and speeding up the progress of pig breeding, and finally a favorable genotype of IGF2 pure line core group was established.