Exon 2 Ovar-DRB1 gene polymorphism in the Iranian Sangsari sheep

The major histocompatibility complex [MHC] plays a central role in the control of disease resistance and immune response. Extensive genetic diversity in MHC genes provides a valuable source for genetic improvement, via selection, in many domestic animals. Exon 2 of the class II MHC, termed Ovar-DRBl in domestic sheep [Ovis aries] has been suggested as important disease resistance and immune response gene. We characterized Ovar-DRBl in DNA samples from 138 individuals of a population of the Iranian Sangsari sheep breed using PCR-RFLP. Eight DRB1 alleles were identified among Iranian Sangsari sheep, including one previously unrecognized allele. Eight homozygous genotypes were observed: a, b, c, d, f, g, h andN. Genotype bb was the most common pattern [46 of 138]. Heterozygous genotypes [ag, cb, cd, bf, and bN] were also observed. The observed homozygosity and heterozygosity values were 0.6377 and 0.3623, respectively, vs expected values of 0.220 and 0.779. Iranian Sangsari population deviate significantly from the theoretical proportions [FIS = 0.5283; p = 0.0005]. In conclusion, PCR-RFLP analysis allows rapid identification of Ovar-DRBl types and discrimination of homozygous and heterozygous genotypes. This study indicates that the exon 2 region of the Ovar-DRBl gene is highly polymorphic in the Iranian Sangsari sheep breed

Typing of Ovar-DRB1 second exon with PCR-RFLP technique in Iranian Shaul Sheep

Several studies have focused on polymorphisms of major histocompatibility complex [MHC] in sheep, Ovar-MHC. This molecule 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 is associated with MHC. Numerous molecular genetic investigations have been undertaken to detect polymorphisms of MHC genes and their association with resistance to infectious diseases. We have examined Ovar-DRB1 in DNA samples of 82 Shaul Sheep using polymerase chain reaction [PCR] and restriction fragment length polymorphism [RFLP] method. Identities of 8 different patterns and 5 distinct DRB1 alleles among Iranian Shaul Sheep have been determined. PCR-RFLP analysis allows rapid identification of Ovar-DRB1 types and enables rapid discrimination between homozygotes and heterozygotes. Data obtained from the present study have revealed that the exon 2 region of Ovar-DRB1 was highly polymorphic in sheep. So PCR-RFLP can be applied to the analysis of this locus