Polymorphism And Association Analysis Of MC4R、IGF2 And VRTN Genes With Production Traits In Large White Pigs

With the development of molecular biology and biotechnology,molecular marker assisted selection has been widely used in animal breeding.The advent of SNPS（single nucleotide polymorphism）,a new generation of molecular markers,speed up the process of the pig breeding and enable the selection of related traits in DNA levels.In this study,PCR-RFLP technique was used to detect SNP polymorphisms in MC4R(melanocortin 4 receptor,IGF2（insulin-like growth factor 2）and VRTN（vertebrae development homolog）three functional genes and the association analysis with production traits were conducted in the Large White pigs.The results were shown as following:（1）The MC4 R gene regulates genes related to fat deposition.According to the correlation analysis results,the Asp298 Asn loci of MC4 R gene which has three genotypes（AA,AG and GG）was significantly associated with back fat thickness and days at 100 kg in American and France Large White pigs（P < 0.01）.The allele G was the advantage allele and associated with lower back fat thickness and faster growth speed.In addition,additive effect of MC4 R gene was significant at these two traits（P < 0.01）.（2）The IGF2 is a key growth factor and plays an important role in cell growth,tissue differentiation and embryo growth.According to the correlation analysis results,the Intron3 G3072 A loci of IGF2 gene was significantly associated with back fat thickness,birth weight,days at 100 kg and the eye muscle area traits（P<0.01）.The allele A was the advantage allele,and could significantly increase the backfat thickness,birth weight,the eye muscle area and promote growth speed（P<0.01）.In addition,IGF2 gene exerted very significant additive effect in these traits（P < 0.01）.（3）The VRTN gene is the functional gene affecting the development of the vertebral number.Association analysis results showed that the g.20311₂0312ins291 loci of VRTN gene had significant effect on body length,left teat number,teat number and days at 100kg（P < 0.05）,and has highly significant effect in body length and growth speed（P < 0.01）.The 2 allele is the advantage allele of increasing body length,teat number and growth speed.VRTN gene exerted in teat number（P < 0.05）,highly significant significantly additive effect of body length and growth speed（P < 0.01）.Taken together,by validating the association of MC4 R,IGF2 and VRTN gene with production traits,this study provides reliable theory basis for marker assisted selection of economically important traits in Large White pigs.