alpha-2 adrenergic receptors can be subdivided into three related subtypes which are conserved in humans, rats, and mice. In the mouse, these receptors are encoded by three genes (Adra-2a, Adra-2b, Adra-2c). To gain insight into the evolution of this multigene family and to investigate whether these genes are candidates for previously identified mouse mutations, we have determined the map positions of the Adra-2b and Adra-2c genes. The Adra-2a gene has been previously mapped to mouse Chromosome (Chr) 19 (Oakey et al. Genomics 10, 338-344, 1991). Using segregation among recombinant inbred strains of a single-stranded conformational polymorphism specific for alleles of Adra-2b and Adra-2c, we present map positions for these genes on mouse Chrs 2 and 5, respectively. In the case of Adra-2b, these results have been confirmed by an analysis of somatic cell hybrids. In addition, we generate AKXD recombinant inbred strain distribution patterns for 11 previously defined SSLP microsatellite markers, further refining the haplotype maps for these chromosomes. Finally, several candidate mouse mutations that map close to Adra-2b and Adra-2c are discussed.