The HLA B17,BfS,C4A6,B1,DR7 and DQw3.2 Supratype Marks an Extensive Chromosomal Segment Shared Between Different Ethnic Group

Abstract

Previously, we have shown that the supratype defined by HLA B17,BfS,C4A6,B1,DR7, as well as a specific 12kb BglII/A1u7 fragment (17,6,1,7), occurs in Caucasoids and Orientals with population frequencies of approximately 1 to 6% an 6% respectively (1). It is often assumed that marked polymorphism of MHC loci reflects increased susceptibility to mutational and recombinant events important in generation of functional diversity. As a consequence, conservation of MHC supratypes between different racial groups would not be expected. Since HLA B17,DR7 may be distinguished serologically and at the genomic level from other DR7-bearing supratypes (2,3), we have examined genomic DNA and DQ subtypes in a further attempt to distinguish between the 17,6,1,7 supratype in different ethnic groups.