Identification of MspI polymorphism in the Intron-I of cGH Gene and its association with egg production traits in chicken

The chicken growth hormone (cGH) gene is considered as one of the most important candidate genes that can influence chicken performance traits because of its crucial function in growth, egg production, reproduction and metabolism. The study was conducted on cGH gene polymorphism in Kadaknath, Kadaknath cross and Synthetic colored dual type birds using polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method. The 770 bp PCR product was obtained and digested with MspI restriction enzyme. Three different RFLP patterns were obtained at two restriction sites corresponding to AA, AB and BB genotypes. The allelic frequencies in indigenous Kadaknath, Kadaknath cross and Synthetic colored dual type birds for A allele were found to be 0.49, 0.64 and 0.46 and for B allele 0.51, 0.36 and 0.54 respectively. The highly significant Chi-square value in Kadaknath cross showed that the population is not in Hardy Weinberg equilibrium, however non significant Chi-square value in other two breeds showed that the population is in equilibrium. The least squares analysis of variance for different genotypes in all the three breeds revealed non significant differences (P<0.05) for age sexual maturity, egg production up to 40 week and 52 weeks of age and egg weight at 40 weeks. It is concluded that the synthetic colored dual type birds with BB genotype for earlier sexual maturity and higher egg production and Kadaknath birds with AB genotype for higher egg weight may be selected as parents for future breeding.