4 POLYMORPHIC MARKERS ON RAT CHROMOSOME-12 FORM A SINGLE LINKAGE GROUP

Four PCR-typable polymorphic markers were mapped to rat chromosome 12 by linkage analysis of F-2 intercross progeny of Fischer (F344/N) and Lewis (LEW/N) rat strains. The markers formed a single linkage group, covering 27.7 cM, with the following order and distance between marker s: plasminogen activator inhibitor (Planh)-0.0 cM-phosphoenolpyruvate carboxykinase-related sequence 2 (Pepckr2)-15.4 cM-anonymous marker (D 12N155)-12.3 cM-serine dehydratase (Sdh). All markers were identified and genotyped by PCR analysis of simple sequence repeats. The gene enc oding Planh was previously assigned to rat chromosome 12 which allowed us to assign the entire linkage group to this chromosome. These marke rs were highly polymorphic in 13 additional inbred rat strains (BUF/N, BN/SsN, WKY/N, MNR/N, LER/N, WBB1/N, WBB2/N, MR/N, LOU/MN, SHR/N, ACI /N, SR/Jr and SS/Jr). These markers should be useful tools for further genetic studies in rats.