Dematiaceous fungal pathogens: analysis of ribosomal DNA gene polymorphismby polymerase chain reaction-restriction fragment length polymorphism

Restriction fragment length polymorphisms (RFLP) of ribosomal gene small su bunit (SSU rDNA) and internal transcribed spacer (ITS) regions was examined in 12 isolates of dematiaceous agents of chromoblastomycosis and phaeohyph omycosis. The amplicon length of the fragment ITS1-ITS4, comprising the 5.8 rDNA and ITS1-ITS2 spacers, ranged in size from 620 to 690 bp. This result indicated a polymorphism of size in this region. Additionally the RFLP pro files showed a high degree of inter- and intra-specific variability. In con trast, the SSU rDNA amplification, using NS1-NS2 primers, originated a frag ment of approximately 570 bp and its restriction profile proved to be well conserved among the species studied and was clustered into only two genetic ally heterogeneous groups, the first one formed by Fonsecaea pedrosoi and F onsecaea compacta and the second one formed by Cladophialophora (Cladospori um) carrionii, Cladophialophora (Xylohypha) bantiana, Phialophora verrucosa and Rhianocladiella species.