Differences among chitin synthase I gene sequences in Trichophyton rubrum and T. violaceum.

Nucleotide sequences of chitin synthase 1 (CHS1) gene were analysed for the phylogenetic relation between Trichophyton violaceum and T. rubrum, including two isolates of T. raubitschekii and one isolate of T. rubrum var. nigricans. About 620-bp genomic DNA fragments of the CHS1 gene were amplified from these dermatophytes by polymerase chain reaction (PCR) and sequenced. The CHS1 nucleotide sequences of these dermatophytes showed more than 95% similarity between the species. The phylogenetic analysis of their sequences revealed that T. rubrum was genetically distinct from T. violaceum. The specific restriction endonuclease site for HinfI was present in the CHS1 gene sequence of T. rubrum but not in that of T. violaceum. A molecular analysis of CHS1 genes will provide useful information for the identification of these Trichophyton species and the understanding of their evolution.