Sexual reproduction and the evolution of microbial pathogens.
Three common systemic human fungal pathogens--Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus--have retained all the machinery to engage in sexual reproduction, and yet their populations are often clonal with limited evidence for recombination. Striking parallels have emerged with four protozoan parasites that infect humans: Toxoplasma gondii, Trypanosoma brucei, Trypanosoma cruzi and Plasmodium falciparum. Limiting sexual reproduction appears to be a common virulence strategy, enabling generation of clonal populations well adapted to host and environmental niches, yet retaining the ability to engage in sexual or parasexual reproduction and respond to selective pressure. Continued investigation of the sexual nature of microbial pathogens should facilitate both laboratory investigation and an understanding of the complex interplay between pathogens, hosts, vectors, and their environments.
Heitman
Joseph
J
Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA. heitm001@duke.edu
D000818:Animals; D001232:Aspergillus fumigatus / Q000472:pathogenicity / Q000502:physiology; D005075:Biological Evolution; D002176:Candida albicans / Q000472:pathogenicity / Q000502:physiology; D003455:Cryptococcus neoformans / Q000472:pathogenicity / Q000502:physiology; D056890:Eukaryota / Q000472:pathogenicity* / Q000502:physiology; D006801:Humans; D003904:Mitosporic Fungi / Q000472:pathogenicity* / Q000502:physiology; D010838:Phytophthora / Q000472:pathogenicity / Q000502:physiology; D010963:Plasmodium falciparum / Q000472:pathogenicity / Q000502:physiology; D012100:Reproduction, Asexual; D012723:Sex; D014122:Toxoplasma / Q000472:pathogenicity / Q000502:physiology; D014346:Trypanosoma brucei brucei / Q000472:pathogenicity / Q000502:physiology; D014349:Trypanosoma cruzi / Q000472:pathogenicity / Q000502:physiology