Accession Number : ADA447569


Title :   Geographic Differentiation of Francisella Tularensis using Molecular Methods


Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH


Personal Author(s) : Dempsey, Michael P


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a447569.pdf


Report Date : May 2006


Pagination or Media Count : 193


Abstract : Franciscella tularensis is a category-A bio-threat agent posing significant concern to both warfighter and civilian. The four subspecies are tularensis, holarctica, mediaasiatica, and novicida with tularensis being most virulent in humans. F. tularensis species have been isolated throughout the Northern Hemisphere, but subsp. tularensis isolates appear restricted to North America. The research described here involved identification and characterization of genetic differences between F. tularensis subspecies and the correlation of genetic markers with geographic variation. The F. tularensis genome is highly conserved among all subspecies when evaluated by such methods as pulsed-field gel electrophoresis, but newer molecular methods offer potential for higher resolution. The present work was based on previous comparative genomic hybridization (CGH) studies that identified several regions of difference (RD) between F. tularensis subspecies. The working hypothesis was that transposon-associated insertion-sequence (IS) elements are the primary driving factor in F. tularensis subspecies divergence. Analysis of these RD showed that only a small number of genes within subsp. tularensis are absent from subsp. holarctica, and all RD were associated with IS elements. The second hypothesis was that geographic-specific subpopulations can be differentiated with advanced molecular methodologies. CGH-testing of a large global F. tularensis strain collection resulted in discovery of a novel IS-associated RD within holarctic strains, referred to as RD(sub spain). Confirmation of this finding was demonstrated by PCR analysis of a global DNA repository, and RD(sub Spain) was found to be restricted to Spain and France. Paired-end sequence mapping (PESM) was used to catalogue additional candidate differential genes.


Descriptors :   *MOLECULES , *GEOGRAPHY , *FRANCISCELLA TULARENSIS , *GENETIC MAPPING , METHODOLOGY , HIGH RESOLUTION , CORRELATION , FRANCE , HYBRIDIZATION , NORTHERN HEMISPHERE , NORTH AMERICA , HYPOTHESES , GENES , LIMITATIONS , VARIATIONS , HUMANS


Subject Categories : Microbiology
      Geology, Geochemistry and Mineralogy
      Atomic and Molecular Physics and Spectroscopy


Distribution Statement : APPROVED FOR PUBLIC RELEASE