Dermatophyte speciation processes reconciled with current phylogenetic species concepts.

Area of Science:

• Mycology
• Evolutionary Biology
• Medical Microbiology

Background:

• The Arthrodermataceae family, encompassing dermatophytes, originated with sexual cycles and clonal propagation.
• Keratinolytic abilities facilitated a transition to dermatopathogenicity, initially dependent on soil-associated animal hosts.
• Adaptation to non-soil nesting animals led to clonal lineages with altered morphology and physiology.

Purpose of the Study:

• To review current species concepts within dermatophytes and related fungi.
• To contrast evolutionary perspectives using population biology tools versus adaptive factors.
• To address practical steps for accurate clinical laboratory identification.

Main Methods:

• Review of evolutionary pathways and speciation processes in dermatophytes.
• Analysis of population biology tools and their limitations in clonal lineages.
• Examination of morphological and physiological adaptations.

Main Results:

• Traditional population biology tools may distort the understanding of clonal speciation.
• Adaptive factors driving host switching are more dynamic than neutral markers.
• Some species concepts are supported in lineages previously reduced in rank, e.g., Trichophyton indotineae, T. interdigitale, T. soudanense.

Conclusions:

• Accurate species concepts are vital for reliable clinical identification of dermatophytes.
• The diversity within species like Trichophyton tonsurans warrants further research into clinical genotypic differences.
• Understanding evolutionary history aids in refining fungal pathogen diagnostics.