DNA sequence analysis of the HLA-DRw12 allele

The complete DNA sequence of a DR beta chain cDNA encoding the DRw12 allele has been determined. The sequence of this DRB1 allele reveals a structural relationship to the group of other DRB1 genes found on DRw52 haplotypes, such as DR3, -w11, -w13, -w14, and -w8. The structural similarities among this group of alleles are particularly evident in the first hypervariable as well as in the 3' untranslated region. The second hypervariable region contains a unique sequence not identified in any other DRB1 allele. The third hypervariable region appears to have arisen by gene conversion events involving two DRB1 chain genes, DR7 and DR1 or DR2/Dw21.