title: HLA-DRB9--possible remnant of an ancient functional DRB subregion.
abstract: The DRB subregion of the HLA complex contains, in addition to the functional genes, a number of pseudogenes and gene fragments. Fourteen kilobases of DNA were sequenced from the segment upstream of the DRB9 gene fragment, as well as shorter segments from different HLA and corresponding ape haplotypes. The analysis of the sequences and restriction fragments indicates that the segment is a remnant of an ancient DRB subregion which may have been functional before the primate radiation and which later became the source of extant functional DRB genes in various primate groups, different ones in different groups. The remnant segment has remained constant in its organization for at least 4 million years. This constancy contrasts with the variability of the adjacent functional part of the DRB subregion occupied by the DRB1 and other loci. The constancy may be related to the monomorphism and evolutionary conservation of the DRA locus.
authors.affiliation: Max-Planck-Institut für Biologie, Tübingen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Gongora
authors.forename: F
authors.initials: F
authors.lastname: Figueroa
authors.forename: C
authors.initials: C
authors.lastname: O'Huigin
authors.forename: J
authors.initials: J
authors.lastname: Klein
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D005091:Exons; D005802:Genes, MHC Class II; D006684:HLA-DR Antigens / Q000235:genetics*; D015803:HLA-DR3 Antigen / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D010802:Phylogeny; D011544:Pseudogenes; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D017931:DNA Primers; D006684:HLA-DR Antigens; D015803:HLA-DR3 Antigen; D004247:DNA