Presence of solitary exon 1 sequences in the HLA-DR region

摘要

The HLA-DR subregion of the human major histo-compatibility complex (Mhc) contains genes coding for the alpha (the DRA gene) and the beta (the DRB gene) chains. There is a single DRA locus and nine DRB loci (DRB1 through DRB9). not all of which are present in a single haplotype (KLEIN et al. 1991). There are five different groups of DR haplotypes in humans: DR1 (major haplotypes DR1 and DRW), containing DRB1 and DRB6 loci: DR51 (haplotypes DR15 and DR16) with one additional locus, DRB5; DR52 (haplotypes DR3 and DR11-DR14), comprising two genes, DRB1 and DRB3, and one pseudogene, DRB2; DR8 (haplotype DR8) consisting of a single functional locus, DRB1; and, finally, DR53 (haplotypes DR4, DR7, and DR9). with two genes DRB1 and DRB4, and two pseudogenes. DRB7 and DRB8. All the haplotypes carry one additional pseudogene, DRB9. centromeric to DRA and consisting of a solitary exon 2 and flanking introns (MEUNIER et al. 1986; GONGORA et al. 1996).