Generation and maintenance of diversity in the cattle MHC class I region

J Birch, Lisa Murphy, Niall MacHugh, Shirley A Ellis

Research output: Contribution to journalArticlepeer-review


Major histocompatibility complex (MHC) class I genes play a crucial role in the immune defence against intracellular pathogens. An important evolutionary strategy is to generate and maintain a high level of diversity in these genes. Humans express three highly polymorphic classical MHC class I genes (HLA-A, HLA-B and HLA-C). In contrast, some species, for example rat and rhesus macaque, maintain diversity by generation of haplotypes that vary considerably with regard to the number and combination of transcribed genes. Cattle appear to use both strategies. We show that various combinations of six apparently classical genes, three of which are highly polymorphic, are transcribed on different haplotypes. Although additional sequences were identified in both cDNA and gDNA, it was not possible to assign them to any of these defined genes. Most were highly divergent or were non-classical class I genes. Thus, we found little evidence for frequent duplication and deletion of classical class I genes as reported in some other species. However, the maintenance of class I diversity in cattle may involve limited gene shuffling and deletion, possibly as a result of unequal crossing-over within the class I region.
Original languageEnglish
Pages (from-to)670-9
Number of pages10
Issue number8
Publication statusPublished - Aug 2006


  • Amino Acid Sequence
  • Animals
  • Cattle/genetics
  • Cattle/immunology
  • Evolution, Molecular
  • Gene Duplication
  • Genes, MHC Class I/genetics
  • Genetic Variation
  • Haplotypes
  • Histocompatibility Antigens Class I/genetics
  • Molecular Sequence Data
  • Sequence Homology, Amino Acid


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