Polymorphism of Myostatin Gene in Intron 1 and 2 and Exon 3, and Their Associations with Yearling Weight, Using PCR-RFLP and PCR-SSCP Techniques in Zel Sheep
The aim of present study was to investigate myostatin gene polymorphism and its association with yearling weight records in Zel sheep using PCR-RFLP and PCR-SSCP methods. Blood samples were collected from 200？Zel sheep, randomly, and DNA was extracted using modified salting out method. Polymerase chain reaction was carried out to amplify 337, 222, and 311？bp fragments, respectively, comprising a part of exon 3, intron 1, and intron 2 of myostatin gene. In addition, exon 3 was digested by HaeIII enzyme under RFLP method, and introns 1 and 2 were studied using SSCP. Under RFLP method, all samples showed mm genotype. Under SSCP method, intron 1 was also monomorph but intron 2 was polymorph (AA, AB, and BB). The allelic frequencies for A and B were 75.5 and 24.5%, respectively. This locus was not in Hardy-Weinberg equilibrium ( ), and there was no significant effect of myostatin gene on yearling weights. 1. Introduction Considerable progress in farm animal breeding has been made in the last few decades, but achieving greater understanding in the improvement of meat quality was very slow before molecular markers became an accessible technology with wide applications in breeding methods [1]. Meat quality is one of the important economic traits in domestic animals. Determination of meat quality requires analysis and classification of fat content, composition, tenderness, water-holding capacity, color, oxidative stability, and uniformity. Meat quality is affected by several factors such as breed, genotype, feeding, fasting, preslaughter handling, stunning, slaughter methods chilling, and storage conditions [2]. Finding of main genes responsible for meat quality will benefit the producers. In recent years, a lot of works have been performed in this field to find potential genes or chromosome regions associated with the meat quality traits in different farm animals, including cattle, sheep, and chicken. Myostatin (MSTN) or growth differentiation factor-8 (GDF-8) is a member of the mammalian growth transforming family (TGF-beta superfamily), which plays an important role in the regulation of embryonic development and tissue homeostasis in adults [3]. They are known to block myogenesis, hematogenesis and enhance chondrogenesis as well as epithelial cell differentiation in vitro. In mice, null mutants are significantly larger than wild-type animals, with 200–300% more skeletal-muscle mass, because of hyperplasia and hypertrophy [4]. Muscular hypertrophy (mh), also known as “double-muscling” in cattle, has been recognized as a physiological character for years [5]
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