Growth hormone gene polymorphism and its correlation with different traits in Bantam and White Leghorn chicken

Molecular genetic selection on individual genes is a promising method to genetically improve economically important traits in chickens. The chicken growth hormone gene (cGH) was amplified from 36 Bantam, 53 Bantamised White Leghorn and 43 White Leghorn birds. The PCR amplification yielded approximately 1200 bp fragment against an expected fragment of 1165 bp, indicating the probability of an insertion or duplication of some sequence. Restriction enzyme digestion of PCR product with Mspl yielded five band/fragment patterns, suggesting two Mspl sites, one already reported at 600 bp position and an additional one at 500 bp position in the 1200 bp segment. Two restriction sites could explain the four patterns. However, the fifth pattern observed might be due to duplication of GH gene. Correlation of cGH/Msplpatterns with age at first egg (APE), body weight (at 20 and 36 weeks of age) and egg production (upto 40 and 60 weeks of age) was estimated. There were significant (P<0.05) differences among the three breed groups for body weights, age at first egg and egg production. However, frequency of RFLP patterns did not differ significantly for these traits. Dendrogram constructed to portray the phylogenetic relationship among these birds showed that Bantamised White Leghorn breed is at equal genetic distance from Bantam and White Leghorn.