Study of Polymorphism in Exon 4 of GH Gene and Exon 10 of GHR Gene and their Associati on with Carcass Traits in Zel Breed Sheep Using PCR-SSCP

One of the goals of identifying loci related to quantitative traits is to find the genes that affecting economic traits related to growth,  which can be of particular importance in the progress of breeding programs. The aim of the present study was to identify the polymorphisms of GH and GHR genes and their association with carcass traits in Zel sheep using PCR-SSCP.

After collecting blood samples from157 Zel sheep, DNA was extracted using modified salting-out procedure. PCR was done to amplify fragments with length of 214 and 218 bp from exon 4 of GH and exon 10 of GHR genes, respectively.  For detection of polymorphisms in each marker site the SSCP and sequencing methods were used.

The results showed the presence of polymorphism in GH gen site; however, no difference was observed among banding patterns for GHR gene. Genotypes 1 and 2 of GH gene were obtained with frequencies of 43.71 and 56.29, respectively.

The sequencing results showed 5 mutations for GH gene in the studied population. No significant associations of the available genotypes in the exon 4 of GH Gene were observed for any trait. In relation to the third structure of mutated protein for both patterns, the results indicated the predicted protein contains only two chains and consequently lacks of performance, compared with the reference protein. Therefore, the studied marker in the GH gene  can not be considered as an effective marker on carcass traits in Zel sheep breed.