Two new HLA DRB1 alleles found in African Americans: implications for balancing selection at positions 57 and 86

Tissue Antigens. 1992 Aug;40(2):69-74. doi: 10.1111/j.1399-0039.1992.tb01962.x.

Abstract

Two new DRB1 alleles have been identified (DRB1*0303 and DRB1*0805) in African Americans that differ from known DRB1 alleles only by a glycine to valine exchange at position 86. The novel DRB1*0303 allele, found in one individual, has the same DQA1*0401-DQB1*04 haplotype as DRB1*0302, suggesting that it may be a recent diversification of *0302. The novel DRB1*0805 allele, identified in 4 individuals, was found on two haplotypes, sharing a DQA1*0501-DQB1*0301 haplotype with DRB1*0804, and a DQA1*0102-DQB1*0602 haplotype found with DRB1*0801 in some African populations. DRB1*0805 differs from *0804 only at position 57 and differs from *0801 only at position 86. Assuming that DRB1*0801 and DRB1*0802 are ancestral, based on their distribution in various human populations, DRB1*0805 may have been generated twice by two independent mutations or gene conversion events at each of these positions. Alternatively, DRB1*0805 may have arisen from a single gene conversion event (or mutation) and recombined to generate multiple DR-DQ haplotypes. These findings increase the number of DRB1 allelic pairs that differ only at position 86 to 9, suggesting strong balancing selection at this position. A number of DRB1 alleles for DR8 and DR4 also differ only at position 57, a site previously postulated to be strongly influenced by balancing selection in DQB1 alleles by phylogenetic analysis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Africa
  • Alleles*
  • Amino Acid Sequence
  • Base Sequence
  • Black People / genetics*
  • Black or African American
  • DNA / genetics
  • HLA-DR Antigens / genetics*
  • HLA-DRB1 Chains
  • Haplotypes / genetics
  • Histocompatibility Antigens Class II / genetics*
  • Humans
  • Molecular Sequence Data
  • United States

Substances

  • HLA-DR Antigens
  • HLA-DRB1 Chains
  • Histocompatibility Antigens Class II
  • DNA

Associated data

  • GENBANK/M81743
  • GENBANK/M87543