GENETIC DIVERSITY AMONG BORRELIA-BURGDORFERI ISOLATES FROM WOOD RATS AND KANGAROO RATS IN CALIFORNIA

Twenty-nine Borrelia burgdorferi isolates, obtained from dusky-footed wood rats (Neotoma fuscipes) and California kangaroo rats (Dipodomys c alifornicus) in California, were analyzed genetically. Chromosomal DNA was examined by restriction endonuclease analysis (REA) and gene prob e restriction fragment length polymorphism. Pulsed-field gel electroph oresis was used to analyze the plasmid profiles of the isolates. REA, the method with the greatest discrimination, disclosed 24 distinct res triction patterns among the 29 isolates. These restriction patterns we re sorted into four restriction fragment length polymorphism groups on the basis of their gene hybridization patterns. Results of the REA an d plasmid profile analysis supported this grouping. The degree of gene tic diversity among Californian isolates demonstrated by our findings is greater than that previously reported among other groups of North A merican isolates and is similar or greater than the diversity reported among European isolates.