DNA homology studies in the taxonomy of dermatophytes

The taxonomy of the dermatophyte genera Trichophyton, Microsporum and Epidermophyton was investigated by determinations of DNA homology. DNA extracted from 10 isolates (seven species) of dermatophytes was reannealed by hydroxyapatite chromatography. DNA homology levels of 65-80% corresponded to species within a single genus. There was a general agreement with established classification, particularly in assigning species to separate genera. DNA from the Trichophyton state of Arthroderma benhamiae (NCPF 456) showed 71 and 76% homology with DNA from T. mentagrophytes (NCPF 224) and T. rubrum (NCPF 5034) respectively. T. terrestre showed low homology (25%) when compared with the other species of dermatophytes tested.