Phylogeny and dating of some pathogenic keratinophilic fungi using small subunit ribosomal RNA.

ABSTRACT

The phylogenetic relationship of representative members of the genera Trichophyton, Microsporum and Epidermophyton was studied. 844 base pairs were compared after sequencing the nuclear 18S ribosomal RNA gene spanning the most variable area within the central 600 bases of this gene. The dermatophytes, which are monophyletic in origin, could be classified most effectively when placed as a subgroup in the Onygenales, Ascomycotina. The calculated radiation time was about 50 million years ago. The early cenozoic adaptive explosion of mammals, which can serve as a host for the keratinophilic fungi, provides corroboration for proximate co-evolution.