Genetic Variability in Growth Hormone Gene and Association between Restriction Fragment Length Polymorphisms (RFLP) Patterns and Quantitative Variation of Live Weight, Carcass, Behaviour, Heterophil and Lymphocyte Traits in Japanese Quails

Growth hormone gene plays a critical role in regulating growth and metabolism which leads to potential correlations between the polymorphisms of this gene and economic trait. A 776 bp fragment within the intron 1 region of the growth hormone gene from 346 individuals of an F2 population of Japanese quail was amplified. The polymerase chain reaction (PCR) product was digested using MspI restriction enzyme. restriction fragment length polymorphisms (RFLP) analysis revealed three restriction sites, which led to four different restriction fragments. Four distinctive alleles (A, B, C, and D) and four different genotypes (AA, AB, AC, and AD) were identified in this population. The results indicated that the population deviated from the Hardy-Weinberg equilibrium (P<0.005). The observed heterozygosity and Shannon's information indexes were 0.720 and 0.560, respectively, which demonstrated high diversity in this population. There was a significant association between RFLP patterns and live weight at four and five weeks of age, carcass weight, breast weight and proportion of the internal organs. Carcass weight of the AB birds was less than that of other genotypes (P<0.05). These results suggested that growth hormone gene can be used as a candidate gene for marker-assisted selection to improve performance in Japanese quails.