title: Migration of a novel DQA1* allele (DQA1*0502) from African origin to North and South America.
abstract: A PCR-based strategy termed DHDA has recently been developed which reveals DQA1 and DQB1 allelic polymorphism through gel retardation following electrophoresis. This HLA-typing strategy improves the efficiency of identifying previously undetected DNA sequence polymorphisms. DHDA has been utilized to perform DQA1 genotypic analysis in non-Caucasian populations and has resulted in the identification of a novel allele, DQA1*0502 (designated by the WHO nomenclature committee). This new allele has been found in Africans and South and North Americans of black racial ancestry and is geographically consistent with the African diaspora during the 15th-19th centuries. DQA1*0502 represents a single C-to-G transversion in codon 59 (exon 2) and results in an amino acid change from proline to arginine. Although MHC genes are highly polymorphic, this DQA1*0502 substitution is unique, as it represents an amino acid change at a position assessed previously to be conserved in the human DQ alpha polypeptides.
authors.affiliation: Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Zimmerman
authors.forename: P M
authors.initials: PM
authors.lastname: Phadke
authors.forename: A
authors.initials: A
authors.lastname: Lee
authors.forename: L H
authors.initials: LH
authors.lastname: Elson
authors.forename: E
authors.initials: E
authors.lastname: Aruajo
authors.forename: R
authors.initials: R
authors.lastname: Guderian
authors.forename: T B
authors.initials: TB
authors.lastname: Nutman
mesh_terms: D000349:Africa / Q000208:ethnology; D000483:Alleles; D001483:Base Sequence; D044383:Black People / Q000235:genetics*; D004484:Ecuador; D006683:HLA-DQ Antigens / Q000235:genetics*; D059848:HLA-DQ alpha-Chains; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009692:Nucleic Acid Heteroduplexes / Q000032:analysis; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011157:Population Dynamics; D014481:United States; D001741:Black or African American
chemical_list: D006683:HLA-DQ Antigens; D059848:HLA-DQ alpha-Chains; C069050:HLA-DQA1 antigen; D009692:Nucleic Acid Heteroduplexes