الفهرس 
Polymorphism in some ovine genes associated with growth
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Abstract
Myostatin is an inhibitor of skeletal muscle growth and a mutation in the gene coding region leads to increased muscling. Calpains play a major role in post mortem tenderization and calpastatin is the endogenous inhibitor of calpain proteases and regulates the rate and extent of post mortem tenderization. Therefore, they are considered as candidate genes for meat and growth traits. Blood samples were collected from Rahmani (N=28), Ossimi (N=45) and Barki (N=50) sheep and DNA were extracted using DNA extraction kit. Genotypes were determined by PCR amplification followed by single-strand conformation polymorphism (SSCP) method for calpain gene and restriction fragment length polymorphism (RFLP) method for calpastatin and myostatin genes. Based on results, all studied genes were found to be polymorphic in all breeds. Genotype frequencies were found to vary with variant genes in different breeds. In these populations, the three loci showed Hardy-Weinberg equilibrium (P<0.05). In MSTN locus, genotype mm was the highest frequency of both Rahmani and Ossimi breeds while the genotype Mm was the most frequent in Barki sheep. In CAPN locus, BB genotype was the most frequent in Rahmani breed while AA genotype was the most frequent in Ossimi and Barki breeds. In CAST locus, NN genotype was prevalent in Rahmani breed while MN was prevalent in Ossimi and Barki breeds. Preliminary data was obtained about relative correlation of these genotypes to average growth rate/year. However, further study may be conducted to ascertain the association of these polymorphisms with other growth traits