title: Evidence for an HLA-C-like locus in the orangutan Pongo pygmaeus.
abstract: HLA-B and C are related class I genes which are believed to have arisen by duplication of a common ancestor. Previous study showed the presence of orthologues for both HLA-B and C in African apes but only for HLA-B in Asian apes. These observations suggested that the primate C locus evolved subsequent to the divergence of the Pongidae and Hominidae. From an analysis of orangutan Tengku two HLA-C-like alleles (Popy C*0101 and Popy C*0201) were defined as well as three HLA-B-like (Popy-B) alleles. By contrast, no Popy-C alleles were obtained from orangutan Hati, although three Popy-B alleles were defined. Thus an HLA-C-like locus exists in the orangutan (as well as a duplicated B locus), implying that the primate C locus evolved prior to the divergence of the Pongidae and Hominidae and is at least 12-13 million years old. Uncertain is whether all orangutan MHC haplotypes contain a C locus, as the failure to find C alleles in some individuals could be due to a mispairing of HLA-C-specific primers with certain Popy-C alleles. These results raise the possibilities that other primate species have a C locus and that the regulation of natural killer cells by C allotypes evolved earlier in primate evolution than has been thought.
authors.affiliation: Departments of Structural Biology and Microbiology & Immunology, Sherman Fairchild Building, Stanford University School of Medicine Stanford, CA 94305-5400, USA. peropa@leland.stanford.edu
authors.forename: E J
authors.initials: EJ
authors.lastname: Adams
authors.forename: G
authors.initials: G
authors.lastname: Thomson
authors.forename: P
authors.initials: P
authors.lastname: Parham
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D005805:Genes, MHC Class I; D015236:HLA-C Antigens / Q000235:genetics*; D015186:Hominidae / Q000235:genetics / Q000276:immunology; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011148:Pongo pygmaeus / Q000235:genetics* / Q000276:immunology*; D011323:Primates / Q000235:genetics / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D015236:HLA-C Antigens; D004247:DNA