Detection of polymorphism of Insulin-like growth factor-I (IGF-I) gene in native Aseel chicken breed of Pakistan using PCR-RFLP

Molecular analysis is an easier means to identify desirable genotypes for growth. Candidate gene (s) for growth trait like insulin like growth factor (IGF) has imperative function for growth, body composition, fat deposition, metabolic and skeletal traits and the molecular genetic selection on individual genes is a very efficient method to genetically improve economically important traits in chickens. In the present study, polymorphism of the promoter and 5' untranslated region of IGF-I gene of nativeAseel, was investigated. In order to evaluate the IGF-I gene polymorphism, we used the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Feather samples were collected at random from 50 Aseel chickensof Pakistan. Genomic DNA was extracted using modified salting-out PCI (Phenol: Chlorophorm: Iso-amylacohol) method and amplified by polymerase chain reaction. The promoter and 5' untranslated region of the 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 and then finally on confirmation of amplification the ampliconswere digested Hinf-I restriction enzyme and this revealed two alleles A and B having all three combinations of genotypes i.e. AA, AB were found. Data were analyzed using Pop Gene 3.1 software package. Allele frequencies (A and B) were 0.53 and 0.47 while genotypic frequency fo AB (66) was significantly higher than AA (20) and AB (66). The Chi- square (χ2) test did not show any deviation from Hardy–Weinberg equilibrium.