Comparative mapping of the human major histocompatibility complex in different racial groups by pulsed field gel electrophoresis.

The molecular map of the human major histocompatibility complex was examined in multiple examples of various Caucasoid and Japanese major histocompatibility complex supratypes using pulsed field gel electrophoresis. Extensive differences in restriction fragment lengths were observed. However, each supratype showed specific genomic characteristics including deletions, duplications, or insertions supporting the hypothesis that these supratypes are markers of conserved ancestral haplotypes. Some of the gene arrangements are consistent with the deletions or duplications previously described or suggested by conventional DNA techniques and protein typing, while others have not been recognized previously. Characterization of the gene organization within disease-associated ancestral haplotypes will provide new insights into the functional role and evolution of the major histocompatibility complex.