Study of polymorphism of major histocompatibility complex (MHC) classII DRB3 locus in Holstein cattle

Message:
Abstract:
The major histocompatibility complex (MHC) gene encodes cell surface glycoproteins that initiate immune responses by presenting processed antigenic peptides to CD4+ T helper cells. DRB3 is the most polymorphic bovine MHC class II gene which encodes the peptide-binding groove. Since different alleles favour the binding of different peptides، DRB3 has been extensively evaluated as a candidate marker for associations with various bovine diseases and immunological traits. For that reason، the genetic diversity of the bovine class II DRB3 locus was investigated by polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP). This study describes genetic variability in the DRB3 in some Holstein cattle. Holstein cows of Astane ghods farm (n=175) were genotyped for bovine lymphocyte antigen DRB3. 2 allele by polymerase chain reaction and restriction fragment length polymorphism method. Bovine DNA was isolated from aliquots of whole blood. A two-step polymerase chain reaction followed by digestion with restriction endonucleases RsaI، HaeIII and BstYI was conducted on the DNA from Iranian Holstein cattle. In the Iranian Holstein herd studied، we identified 24 alleles. DRB3. 2*22 had the highest allelic frequency (16. 7%)، followed by DRB3. 2*8 (16. 1%)، DRB3. 2*24 (14. 4%)، DRB3. 2*16 (12. 7%). Fifteen allele (DRB3. 2*21، *18،*14، *28، *12، *26، *6، *2،*10، *32، *37، *51، *7، *15، *5) had frequencies <2%. Our results indicate that exon 2 of the DRB3 gene is highly polymorphic in Iranian Holstein cattle.
Language:
Persian
Published:
Animal Sciences Journal, Volume:22 Issue: 84, 2010
Page:
14
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