An improved genetic linkage map of rat chromosome 20

Background and Purpose: Rat chromosome 20 is one of special interest because it contains some diabetogenic genes, such as a major histocompatibility complex (MHC)-linked genetic components and quantitative trait loci. We studied rat chromosome 20, using the backcross progeny between BB/Wor and PVG.R23 rats, and confirmed the genetic linkage map by use of another backcross panel. Methods: Backcross panels were done between BB/Wor and PVG.R23 rats, and BN and KZC rats. Length variations of simple sequence length polymorphism markers were analyzed by use of polymerase chain reaction (PCR) analysis. Alleles of RT1-Bb and RT1-Db were analyzed by use of the PCR-restriction fragment length polymorphism method. Genetic maps of rat chromosome 20 were constructed, using the Map Manager computer program. Results: Fifty-two loci were mapped on rat chromosome 20, Genetic length was 57.9 cM, with average spanning of 1.11 cM between markers. The positions of RT1-N1, Tnf, and RT1-Bb into the MHC region were separated and confirmed by results of two backcross panels in our linkage studies. Conclusions: The genetic linkage map of rat chromosome 20 was improved, and was a useful tool for genetic analysis of a diabetogenic gene(s) and for producing MHC congenic strains.