Genetic diversity of Ustilago maydis strains

Thirty wild isolates belonging to five different locations in Mexico plus t wo laboratory strains of Ustilago maydis were characterized by restriction fragment length polymorphism (RFLP) analysis using 23 different clones as p robes derived from a PstI library and two restriction enzymes. All loci ana lysed presented a high level of polymorphism, including one locus with thir ty one different alleles. Geographical grouping of the populations was base d on Nei's genetic distance and there was no correlation between genetic an d geographic distances among these isolates. Our results suggest that DNA f ingerprinting is a useful method for detecting genetic variation in populat ions of U. maydis. This work demonstrated that considerable genetic variati on may be present within field populations of U. maydis.