- Comparative phylogenetic analysis uncovers what makes a fungal species pathogenic.
- Advances in molecular phylogenetics increase our precision in defining species.
- Emergence of new infectious dimorphic fungal pathogens results in taxonomy shift.
- Gene loss revealed by genomic sequencing shows how fungus adapts to mammalian host.
Dimorphic fungal pathogens are a significant cause of human disease worldwide. Notably, the dimorphic fungal pathogens within the order Onygenales are considered primary pathogens, causing disease in healthy hosts. Current changes in taxonomy are underway due to advances in molecular phylogenetics, population genetics, and new emerging dimorphic fungal pathogens causing human disease. In this review, we highlight evolutionary relationships of dimorphic fungal pathogens that cause human disease within the order Onygenales and provide rationale to support increased investment in studies understanding the evolutionary relationships of these pathogens to improve rapid diagnostics, help identify mechanisms of antifungal resistance, understand adaptation to human host, and factors associated with virulence.