Mojtaba Lotfi, Mohammad Taghi Beigi Nassiri , Hedayatollah Roshanfekr , Jamal Fayazi , Polymorphism of Ovar-DRB1 Second Exon with PCR-RFLP Technique in Arabi Sheep Population of Khuzestan Province, Journal of Animal and Veterinary Advances, Volume 11,Issue 6, 2012, Pages 760-762, ISSN 1680-5593, javaa.2012.760.762, (https://makhillpublications.co/view-article.php?doi=javaa.2012.760.762) Abstract: Major Histocompatibility Complex (MHC) plays a pivotal role in antigen presentation for eliciting immune responses against invading pathogens. The best characterized genetic control of disease resistance and immune response in animals are associated with MHC. Therefore, in this study polymorphism of Ovar-DRB1 in DNA samples of 111 heads Arabi sheep using Polymerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) method was examined. Identities of 18 different patterns and 8 distinct DRB1 alleles among Arabi sheep have been determined. There is not deviation in Ovar-DRB1 gene from Hardy-Weinberg equilibrium in this population, results showed. Obtained results have revealed that the exon 2 region of Ovar-DRB1 was highly polymorphic on Arabi sheep. Keywords: Arabi sheep;MHC;Ovar-DRB1;PCR-RFLP;Khuzestan province;Iran