title: Analysis of intron sequences at the class II HLA-DRB1 locus: implications for the age of allelic diversity.
abstract: Analyses of the coding sequences of HLA class II alleles have revealed high similarity between species, indicating that much of the polymorphism predates the separation of human (Homo) and chimpanzee (Pan), 4-7.4 million years ago. Recent studies of the intron sequences of alleles provide support for a much more recent origin and rapid generation of HLA alleles. At the DRB1 locus, intron analysis indicates that most of the allelic lineages have diverged from each other before the separation of Homo and Pan, consistent with the exon analysis. However, the intron sequences of alleles within lineages are almost identical, indicating that many of the alleles have been generated after the divergence of the Homo and Pan lineages.
authors.affiliation: Department of Medical Genetics, Beijer Laboratory, University of Uppsala, Sweden.
authors.forename: T F
authors.initials: TF
authors.lastname: Bergström
authors.forename: A
authors.initials: A
authors.lastname: Josefsson
authors.forename: H A
authors.initials: HA
authors.lastname: Erlich
authors.forename: U B
authors.initials: UB
authors.lastname: Gyllensten
mesh_terms: D000483:Alleles; D000818:Animals; D019143:Evolution, Molecular; D005802:Genes, MHC Class II; D014644:Genetic Variation; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D007438:Introns / Q000235:genetics*; D002679:Pan troglodytes / Q000235:genetics; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains