RESUMEN
The DRB3 gene is a highly polymorphic major histocompatibility complex [MHC] class II gene and plays an important role in variability of immune responsiveness and disease resistance. In the present study, the MHC class II DRB3 gene in water buffalo [Bubalus bubalis] populations from Northwest regions of Iran was investigated through PCR-SSCP. Genomic DNA was extracted from whole blood samples collected from 50 buffaloes. A 284 bp segment of exon 2 of BuLa-DRB3 was amplified by standard PCR, using locus-specific primers. The PCR products were subjected to a non-denaturing gel electrophoresis. A number of 11 different SSCP patterns indicating allelic variation were identified. The three most frequent patterns 1,4 and 10 accounted for 58% of the total patterns. Results indicated that exon 2 of the BuLA-DRB3 gene is highly polymorphic among the examined animals