Insulin-like growth factor-1 polymorphism and its association with economic traits in Kadaknath and its crossbred birds

Insulin-like growth factor-1 (IGF-1) gene polymorphism has been investigated by PCR-RFLP method on 80 unrelated female birds each of Kadaknath and its crossbred selected randomly from Department of Poultry Science of the University. The 3 different RFLP patterns revealed restriction fragment of 621, 364 and 257 bp sizes in Kadaknath and Kadaknath crossbred birds. This indicated presence of 2 restriction sites at 621 bp (site A) and 364, 257 bp (site B) position in 621bp amplicon. Genotypic frequencies in Kadaknath and Kadaknath crossbred birds were found to be 0.41 and 0.35 for AA genotype, 0.37 and 0.38 for AB genotype and 0.21 and 0.27 for BB genotype, respectively, whereas the allelic frequencies in Kadaknath and Kadaknath crossbred birds were 0.60 and 0.54 for A allele and 0.40 and 0.46 for B allele respectively. The Kadaknath population was in Hardy Weinberg equilibrium, however Kadaknath crossbred population under study was not in Hardy Weinberg equilibrium. The differences between least squares means of various genotypes for age at sexual maturity and adult body weight at 20, 40 and 52 weeks were nonsignificant (P>0.05). Genotype BB was superior for body weight at 20, 40 and 52 weeks in Kadaknath and Kadaknath crossbred birds. Significant breed x genotype interaction was found for egg production at 40 weeks of age and higher egg production was recorded for AA genotype in Kadaknath and AB genotype in Kadaknath crossbred birds. Genotype AA was superior for egg weight at 40 and 52 weeks in Kadaknath and Kadaknath crossbred birds.