Genome variation in Cryptococcus gattii, an emerging pathogen of immunocompetent hosts.
Cryptococcus gattii recently emerged as the causative agent of cryptococcosis in healthy individuals in western North America, despite previous characterization of the fungus as a pathogen in tropical or subtropical regions. As a foundation to study the genetics of virulence in this pathogen, we sequenced the genomes of a strain (WM276) representing the predominant global molecular type (VGI) and a clinical strain (R265) of the major genotype (VGIIa) causing disease in North America. We compared these C. gattii genomes with each other and with the genomes of representative strains of the two varieties of Cryptococcus neoformans that generally cause disease in immunocompromised people. Our comparisons included chromosome alignments, analysis of gene content and gene family evolution, and comparative genome hybridization (CGH). These studies revealed that the genomes of the two representative C. gattii strains (genotypes VGI and VGIIa) are colinear for the majority of chromosomes, with some minor rearrangements. However, multiortholog phylogenetic analysis and an evaluation of gene/sequence conservation support the existence of speciation within the C. gattii complex. More extensive chromosome rearrangements were observed upon comparison of the C. gattii and the C. neoformans genomes. Finally, CGH revealed considerable variation in clinical and environmental isolates as well as changes in chromosome copy numbers in C. gattii isolates displaying fluconazole heteroresistance.
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R37 AI039115 / AI / NIAID NIH HHS / United States
U54 HG003067 / HG / NHGRI NIH HHS / United States
U54HG003067 / HG / NHGRI NIH HHS / United States
R01 AI053721 / AI / NIAID NIH HHS / United States
Intramural NIH HHS / United States
Canadian Institutes of Health Research / Canada
R01 AI50113 / AI / NIAID NIH HHS / United States
R01 AI050113 / AI / NIAID NIH HHS / United States
55000640 / Howard Hughes Medical Institute / United States