Relation of Ultraviolet-Induced Mutations to Speciation in Dermatophytes

Variability of a sort not susceptible to genetic analysis is a frequently observed phenomenon among fungi and bacteria1and is an important interfering factor in the recognition and identification of pathogenic fungi. It is important from the standpoint of any systematic study that the permanence, frequency and extent of such variation be known. In the case of some fungi, mutants have been subjected to genetic analysis.2The sudden appearance, diversity and permanence of the type of variation under discussion and the genetic behavior of analogous variants in neurosporan and in yeasts seem to justify the designation "mutant" for these variants. The published report3of a series of remarkable mutations appearing spontaneously in an old culture of the pathogenic fungus Microsporon gypseum concluded with the hypothesis, "many of the dermatophytes now known as species are only varieties of a single unstable species."4The con