Cytogenetic localization of the growth and reproduction complex (Grc) in the rat and in the mouse and its position in relation to RT1.EC and other loci in the rat MHC

The segment of rat chromosome 20 (RNO20p12) thai contains the classical loci of the major histocompatibility complex (MHC: RT1.A RT1.E) also contains genes affecting growth reproduction and susceptibility ro chemical carcinogens (the Gic) and multiple genes encoding class I MHC antigens (the EC region). The relative positions of the MHC. Gic, and EC region have not been demonstrated explicitly, although they have been postulated from genetic mapping studies. The present study was undertaken to map these region cytogenetically by several different approaches using cosmids specific fur the: Rps 18. Hspa 1 and Bat 1 genes. The order was shown to be. centromere - Rps 18 - Hspa 1 - Bat 1 - EC - Grc.