Detection of polymorphism of the insulin-like growth factor-I (IGF-I) gene in Mazandaran native chicken using PCR-RFLP method

Molecular genetic selection on individual genes is a promising method to genetically improve economically important traits in chickens. The insulin-like growth factor-I (IGF-I) gene may play important roles in growth of multiple tissues, including muscle cells, cartilage and bone. In the present study, polymorphism of the promoter and 5' untranslated region of IGF-I gene of Mazandaran native fowls was investigated. In order to evaluate the IGF-I gene polymorphism, we used the restriction fragment length polymorphism (RFLP) method. Blood samples were collected from randomly chosen 100 Mazandaran native fowls. Genomic DNA was extracted using modified salting-out method and amplified polymerase chain reaction technique. The promoter and 5' untranslated region of the fowl IGF-I gene was amplified to produce a 621 bp fragment. The PCR products were electrophoresed on 2.5% agarose gel and stained by ethidium bromide. Then they were digested of amplicons with PstI, which revealed two alleles A and B. Data were analyzed using Pop Gene 32 software package. In this population, AA, AB, BB genotypes were identified with 25.88, 50.23 and 23.89% frequencies, respectively. Allele frequencies (A and B) were 0.51 and 0.49, respectively. The Chi-square (χ 2 ) test did not show deviation from Hardy–Weinberg equilibrium (P<0.05).