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Human pathogeneic fungi and their close nonpathogenic relatives
B H Bowman1, T J White, J W Taylor
1Roche Molecular Systems, Alameda, California 94501, USA.
Molecular Phylogenetics and Evolution
|August 1, 1996
Summary
Pathogenic fungi are not a single evolutionary group, suggesting multiple origins of disease-causing ability. Closely related nonpathogenic fungi offer potential models for studying fungal pathogens.
Area of Science:
- Mycology
- Evolutionary Biology
- Genetics
Background:
- Understanding the evolutionary relationships between pathogenic and nonpathogenic fungi is crucial for studying fungal diseases.
- Morphological classifications may not accurately reflect evolutionary divergence in fungi.
Purpose of the Study:
- To investigate the evolutionary relationships between key human pathogenic fungi and their closest nonpathogenic relatives.
- To determine if pathogenic fungi form a monophyletic group.
Main Methods:
- Sequencing of small-subunit ribosomal DNA (rDNA) genes from pathogenic and nonpathogenic fungi.
- Phylogenetic analysis using genetic distance and parsimony algorithms.
Main Results:
- Human pathogenic fungi are interspersed among nonpathogenic relatives, indicating multiple independent origins of pathogenicity.
- Specific nonpathogenic fungi (Chrysosporium parvum, Uncinocarpus reesii) are identified as closest relatives to B. dermatitidis and C. immitis, respectively.
- Asexual spore types (conidia) do not represent distinct monophyletic groups.
Conclusions:
- Pathogenicity in fungi has likely evolved multiple times independently.
- Nonpathogenic relatives can serve as valuable model systems for studying pathogenic fungi.
- Phylogenetic analyses can help integrate sexual and asexual fungal classifications.