Polymorphisms of growth hormone (GH) gene and their effects on some growth traits in norduz sheep

Genetic markers or DNA markers are valuable in distinguishing genetic variations between individuals. The advancement of DNA-based DNA markers has had a progressive effect on hereditary studies. Recently, the application of DNA-markers has commonly been used to determine polymorphism in human, animal, aquaculture, and plant fields. There are different types of markers that can be used to identify polymorphism in animals, but the most commonly used ones are RAPD, AFLP, RFLP, mini and micro-satellites and SNPs. The aim of the research was to identify the genetic polymorphisms in growth hormone gene (GH) by using its three different loci named (GHY1, GHY2, and GHY3) in the genome of Norduz sheep. In this research, the PCR-RFLP technique was performed to determine genetic variations in the growth hormone (GH) genes in Norduz sheep. First, genomic DNA were purified from 50 individuals of Norduz sheep, then three sets of primers were chosen to amplify loci of GHY1, GHY2, and GHY. The lengths of PCR products were 599 bp, 690 bp, and 679 bp respectively. Furthermore, three loci were digested with MspI, a DNA endonuclease enzyme. Results displayed that there were no polymorphisms for three loci of GH. Only, one particular genotype AB heterozygous was observed in all individuals whereas genotypes AA and BB were not observed under this investigation. The results of this study have suggested that further affords of the research in GH to detect polymorphisms one should use SNPs which is more reliable technique to identify polymorphisms. Keywords: Growth hormone gene (GH), Genetic Markers, Norduz Sheep, PCR-RFLP.