DNA Fingerprinting and Phylogenetic Analysis of WNIN Rat Strain and Its Obese Mutants Using Microsatellite Markers

Wistar is the oldest rat strain to be introduced in biomedical research, and various stocks of this strain are maintained in laboratories across the globe. The Wistar strain maintained in our facilities is 85 years old and is not typed genetically so far. Recently, two obese mutant rat strains evolved from this stock, one with euglycemia and the other with impaired glucose tolerance. These mutant rat strains, along with the parental Wistar stock and two other rat strains maintained in our facilities (WKY and F-344), were subjected to PCR-based DNA fingerprinting using microsatellite markers to evolve molecular signatures unique to them. Of the 96 markers screened, we identified a marker, leukosianin, that shows polymorphism between the strains tested and thus appears to be quite useful for rat strain identification. Also, the microsatellite data generated were subjected to hierarchical cluster analysis to generate a dendrogram and to estimate the phylogenetic closeness and distance between the rat strains tested. It was observed that the Wistar strain and its mutants maintained in our facility are genetically distinct and phylogenetically separate from the other two standard strains WKY and F-344.