Mapping class I gene sequences in the major histocompatibility complex

The class I glycoproteins of the major histocompatibility complex (MHC) are products of closely linked genes on the 17th chromosome of the mouse. Four highly homologous cell surface proteins, K, D, L, and Qa-2 (refs 1-4), belonging to this multigene family have been analysed. Several additional members ^5-7, M, R, TL, are indicated by biochemical data and recent serological data suggest the family is larger⁸. Recent reports using recombinant DNA technology suggest that the class I system is an extensive multigene family^9-12. In this report we describe results of experiments using restriction enzyme digestion of DNA from a group of standard, congeneic and MHC recombinant mouse strains followed by hybridization to H-2 cDNA probes. Particular bands of hybridization can be assigned to specific H-2 haplotypes and, therefore, to the MHC region of the 17th chromosome. A number of the MHC polymorphic bands have been assigned to genetic map positions in the K and D-L regions of the H-2 complex. Additional class I gene sequences map outside the boundaries of the traditional H-2 complex (K, I, S, D), into the Qa-T1a region. At least one sequence is centromeric to the K locus. Further, amino terminal and carboxy terminal probes show different restriction patterns, suggesting that the exons corresponding to the different domains of the class I glycoproteins may have different evolutionary histories.