title: Genomic islands from five strains of Burkholderia pseudomallei.
abstract: BACKGROUND
  Burkholderia pseudomallei is the etiologic agent of melioidosis, a significant cause of morbidity and mortality where this infection is endemic. Genomic differences among strains of B. pseudomallei are predicted to be one of the major causes of the diverse clinical manifestations observed among patients with melioidosis. The purpose of this study was to examine the role of genomic islands (GIs) as sources of genomic diversity in this species.
  
  
  RESULTS
  We found that genomic islands (GIs) vary greatly among B. pseudomallei strains. We identified 71 distinct GIs from the genome sequences of five reference strains of B. pseudomallei: K96243, 1710b, 1106a, MSHR668, and MSHR305. The genomic positions of these GIs are not random, as many of them are associated with tRNA gene loci. In particular, the 3' end sequences of tRNA genes are predicted to be involved in the integration of GIs. We propose the term "tRNA-mediated site-specific recombination" (tRNA-SSR) for this mechanism. In addition, we provide a GI nomenclature that is based upon integration hotspots identified here or previously described.
  
  
  CONCLUSIONS
  Our data suggest that acquisition of GIs is one of the major sources of genomic diversity within B. pseudomallei and the molecular mechanisms that facilitate horizontally-acquired GIs are common across multiple strains of B. pseudomallei. The differential presence of the 71 GIs across multiple strains demonstrates the importance of these mobile elements for shaping the genetic composition of individual strains and populations within this bacterial species.
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011-5640, USA. Apichai.Tuanyok@nau.edu
authors.forename: Apichai
authors.initials: A
authors.lastname: Tuanyok
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Leadem
authors.forename: Raymond K
authors.initials: RK
authors.lastname: Auerbach
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Beckstrom-Sternberg
authors.forename: James S
authors.initials: JS
authors.lastname: Beckstrom-Sternberg
authors.forename: Mark
authors.initials: M
authors.lastname: Mayo
authors.forename: Vanaporn
authors.initials: V
authors.lastname: Wuthiekanun
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Brettin
authors.forename: William C
authors.initials: WC
authors.lastname: Nierman
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Currie
authors.forename: David M
authors.initials: DM
authors.lastname: Wagner
authors.forename: Paul
authors.initials: P
authors.lastname: Keim
mesh_terms: D042726:Burkholderia mallei / Q000235:genetics*; D022761:Gene Transfer, Horizontal; D014644:Genetic Variation; D044404:Genomic Islands; D012343:RNA, Transfer / Q000235:genetics; D009626:Terminology as Topic
chemical_list: D012343:RNA, Transfer