Polymorphisms of Growth Hormone Gene in a Native Chicken Population: Association with Egg Production

A total of 142 chicken blood samples were collected and a specific primer set was used to amplify a fragment of growth hormone locus using PCR. PCR products were digested with SacI and MspI restriction endonucleases. The amplified fragment digested with SacI enzyme revealed two “+” (wild type) and “-” (normal type) alleles with the frequency of 0.898 and 0.102, respectively. The amplified fragment digested with MspI enzyme revealed three A, B and C alleles with the frequency of 0.599, 0.102, and 0.299, respectively. Frequencies of +/+, +/- and -/- were 0.817, 0.162, and 0.021, respectively, and those of AA, AB, AC, BB, BC, and CC were 0.338, 0.113, 0.409, 0.007, 0.070, and 0.063, respectively, in the studied population. The results of 2 and likelihood ratio tests showed that this population was at Hardy-Weinberg equilibrium with respect to the marker locus. Marker-trait association analysis revealed statistically significant differences between “SacI-RFLP” genotypes for egg production and rate of laying eggs. The relationship between the molecular marker and these traits can be useful to improve the chicken breeding programmes