A continuous restriction map from HLA-E to HLA-F. Structural comparison between different HLA-A haplotypes

The class I region of the human major histocompatibility complex contains genes encoding the classical transplantation antigens (HLA-A, B, and C), at least three new class I genes (HLA-E, F, and G) and many class I pseudogenes (including HLA-H). By pulse field gel electrophoresis and using five rare cutter enzymes, we have constructed a precise and continuous map of 1200 kilobases (kb) around HLA-A. The blots were hybridized with HLA-A, E, and F-specific probes and with new probes derived from yeast artificial chromosomes and cosmids of the class I region. We have compared the genomic organization of the same 1200 kb in three homozygous lymphoblastoid cell lines corresponding to three different HLA haplotypes (A3, A24, and A31). The differences in size observed may have been caused by insertions and deletions and may prove valuable in understanding the evolution of the HLA chromosomal region.