Same-sex mating and the origin of the Vancouver Island Cryptococcus gattii outbreak (Nature, 2005, 437:1360-1364)

報告日期: 2006/05/23
報告時間: 17:10/18:00
報告學生: 楊亞倫 (英文報告)
講評老師: 張珍琦
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Same-sex mating and the origin of the Vancouver

Island Cryptococcus gattii outbreak

Nature. 437, 1360-64 (2005)

 

SpeakerYah-Luen Yang                    Date95.05.23  PM 5:10-6:00

CommentatorDr. Jen-Chyi Chang            placeRoom 602

 

Abstract

Cryptococcus gattii causes life-threatening infection of the pulmonary and central nervous systems in hosts with normal immunity and traditionally has been considered to be restricted geographically to tropical and subtropical climates. (1) In 1999 a C. gattii outbreak emerged on Vancouver Island, Canada. Infection of otherwise healthy individuals and animals on the island is ongoing, indicating an expanded geographical range for this pathogen. (2) At the same time, previous studies have revealed that most Vancouver Island outbreak isolates are sexually fertile, but all areαmating type. (3) To elucidate the origin of the Vancouver Island outbreak and determine whether sex had a role, a large-scale genealogical analysis was conducted with C. gattii isolates collected worldwide. In this paper, the authors utilizes amplified fragment length polymorphism (AFLP) and randomly amplified polymorphic DNA (RAPD) analyses

revealed four major molecular groups (VGI-VGIV) to verify and propose the major and minor genotype are two independent clonal populations present on Vancouver Island. On the other hand, the study groups to further characterize the relationship between the Vancouver Island major and minor genotypes, they analyses an additional loci distributed throughout the genome by MATαintergenic region fingerprints to support major genotype was produced as a result of mating between two closely related α VGII parental strains. At the same time, using a murine intranasal inhalation model to test the differ strain virulence and the each strains relationship to showed a striking difference in virulence for the major and minor genotypes. Finally, the authors propose that the same-sex mating and the origin of the Vancouver Island C. gattii outbreak. These studies demonstrate how cryptic same-sex reproduction can enable expansion of a human pathogen to a new geographical niche and contribute to the ongoing production of infectious spores and inbreeding in host range expansion in the fungal and other kingdoms.

 

References

1.         Kidd, S. E. et al. Proc. Natl Acad. Sci. USA 101, 17258–-17263 (2004).

2.         Hoang, L. M. et al., J. Med. Microbiol. 53, 935-940 (2004).

3.         Fraser, J. A. et al., Eukaryot. Cell 2, 1036–-1045 (2003).