首页 | 本学科首页   官方微博 | 高级检索  
     


Comparison of Francisella tularensis genomes reveals evolutionary events associated with the emergence of human pathogenic strains
Authors:Laurence Rohmer  Christine Fong  Simone Abmayr  Michael Wasnick  Theodore J Larson Freeman  Matthew Radey  Tina Guina  Kerstin Svensson  Hillary S Hayden  Michael Jacobs  Larry A Gallagher  Colin Manoil  Robert K Ernst  Becky Drees  Danielle Buckley  Eric Haugen  Donald Bovee  Yang Zhou  Jean Chang  Ruth Levy  Regina Lim  Will Gillett  Don Guenthener  Allison Kang  Scott A Shaffer  Greg Taylor  Jinzhi Chen  Byron Gallis  David A D'Argenio  Mats Forsman  Maynard V Olson  David R Goodlett  Rajinder Kaul  Samuel I Miller  Mitchell J Brittnacher
Affiliation:Department of Genome Sciences, University of Washington, Campus Box 357710, 1705 NE Pacific street Seattle, Washington 98195, USA. lrohmer@u.washington.edu
Abstract:

Background

Francisella tularensis subspecies tularensis and holarctica are pathogenic to humans, whereas the two other subspecies, novicida and mediasiatica, rarely cause disease. To uncover the factors that allow subspecies tularensis and holarctica to be pathogenic to humans, we compared their genome sequences with the genome sequence of Francisella tularensis subspecies novicida U112, which is nonpathogenic to humans.

Results

Comparison of the genomes of human pathogenic Francisella strains with the genome of U112 identifies genes specific to the human pathogenic strains and reveals pseudogenes that previously were unidentified. In addition, this analysis provides a coarse chronology of the evolutionary events that took place during the emergence of the human pathogenic strains. Genomic rearrangements at the level of insertion sequences (IS elements), point mutations, and small indels took place in the human pathogenic strains during and after differentiation from the nonpathogenic strain, resulting in gene inactivation.

Conclusion

The chronology of events suggests a substantial role for genetic drift in the formation of pseudogenes in Francisella genomes. Mutations that occurred early in the evolution, however, might have been fixed in the population either because of evolutionary bottlenecks or because they were pathoadaptive (beneficial in the context of infection). Because the structure of Francisella genomes is similar to that of the genomes of other emerging or highly pathogenic bacteria, this evolutionary scenario may be shared by pathogens from other species.
Keywords:
本文献已被 PubMed SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号