Growth hormone gene polymorphism in Kadaknath breed of poultry

The chicken growth hormone gene of intron I region from three varieties of Kadaknath breed of poultry was amplified by PCR and a 770 bp product was obtained. The products from each variety (Jet black, Golden and Pencilled) were digested with Msp I (5 U), which recognizes the 5′-C ↓ C G G-3′ sequence. The RFLP pattern revealed restriction fragments of 529, 373, 241 and 156 bp sizes, which indicated the presence of two restriction sites. In total, three RFLP patterns was observed at two restriction sites. The genotypic frequencies obtained for different varieties were tested for equilibrium using chisquare test. The differences among genotypes for all the three varieties were found to be non-significant, which indicated that population was in Hardy-Weinberg equilibrium. The alleles A and A2 were not observed in all the three varieties of Kadaknath breed of poultry. The overall allelic frequencies for A1 and A3 alleles were 0.375±0.016 and 0.625±0.020, respectively for all the three varieties. The highest allelic frequency (0.700±0.011) was obtained for A3 allele in Pencilled variety and lowest (0.300±0.022) for A1 allele was also observed in Pencilled variety. The phylogenetic consensus tree grouped all the three varieties into one cluster. The highest genetic distance (0.0748) was observed between Jet black and Pencilled and smallest (0.0051) between Jet black and Golden varieties. The genetic differences among all the three varieties based on phylogenetic tree were negligible; which indicates non-significant differences among each other. Thus it can be concluded that all the three varieties belonging to the Kadaknath breed of poultry have almost similar genetic base.