GENETIC-STUDIES IN THE GENUS BASIDIOBOLUS .2. PHYLOGENETIC-RELATIONSHIPS INFERRED FROM RIBOSOMAL DNA ANALYSIS

We have investigated genetic relationships among isolated of the genusBasidiobolus by examining restriction site polymorphisms in the ribosomal RNA genes. Approximately 10 kb or rDNA was cloned and employed as a probe of genomic DNA from 12 isolates, of human and saprobic origin, digested with nine restriction enzymes. While we foundB. microsporus Benjamin to be distinct, 9 human isolates designatedB. haptosporus Drechsler,B. meristosporus Drechsler, andB. ranarum Eidam were indistinguishable from one another. In contrast, two unidentified saprobic isolates could be readily differentiated from the human ones. We conclude that all human isolates examined fall within a single monophyletic group, but that significant genetic differentiation has taken place between human and saprobic isolates that is not accounted for in existing taxonomies of the genus. © 1990 Academic Press, Inc.