Main Article Content
Local chickens in Iraq are characterized by low production efficiency. In fact, phenotypic traits such as growth rate is influenced by genes and environmental factors. However, the present study attempts to identify associations between growth rate and polymorphism of TGF-β3 gene in Iraqi local chicken. Seventy-five male birds were used in this study. The restriction enzyme BsrI has been used to detect the target region (1078 bp) in the TGF-β3 gene. A SNP was identified at 9361 position in the exons 3-6 region of TGF-β3 by using a DNA sequencing technique. The genotypic frequencies were 66.67, 17.33 and 16% for AA and CA and CC genotypes respectively. While, the allele frequency of gene A and C were 0.75 and 0.25%, respectively. Generally, during the last period of rearing we noted the best improved significantly (p>0.05) for body weight was recorded in the CA genotype of TGF-β3 gene. In conclusion, the TGF-β3 gene may have broad effects on growth and development. At the same time, polymorphism may be used as a candidate genes of QTL to improve body weight in local chickens.