A study on determination of growth hormone gene polymorphism and its association with some milk composition traits in Zel sheep breed

Growth hormone (GH) is one of important hormones that affect growth and production traits in mammalian. Growth hormone gene has been used as a candidate gene for marker-assisted selection in different ¬domestic livestock species. In this research, for investigation of genetic polymorphism of the gene, blood samples (180 samples) were obtained from animals located in shirang station, Golestan. DNA was extracted from blood samples and a 365 bp fragment from the exon 5 of the ovine growth hormone gene amplificated by polymerase chain reaction. Then PCR products were analyzed by SSCP method on 8% polyacrilamide gel¬. Single strand conformation polymorphism (SSCP) analysis showed three conformational patterns for this gene. There was found no significant difference between milk composition and GH patterns in this population. Results showed a significant difference between observed and expected frequencies indicating that there was not Hardy-Weinberg equilibrium.