title: Differential efficiency in exogenous DNA acquisition among closely related Salmonella strains: implications in bacterial speciation.
abstract: BACKGROUND
  Acquisition of exogenous genetic material is a key event in bacterial speciation. It seems reasonable to assume that recombination of the incoming DNA into genome would be more efficient with higher levels of relatedness between the DNA donor and recipient. If so, bacterial speciation would be a smooth process, leading to a continuous spectrum of genomic divergence of bacteria, which, however, is not the case as shown by recent findings. The goal of this study was todetermine if DNA transfer efficiency is correlated with the levels of sequence identity.
  
  
  RESULTS
  To compare the relative efficiency of exogenous DNA acquisition among closely related bacteria, we carried out phage-mediated transduction and plasmid-mediated transformation in representative Salmonella strains with different levels of relatedness. We found that the efficiency was remarkably variable even among genetically almost identical bacteria. Although there was a general tendency that more closely related DNA donor-recipient pairs had higher transduction efficiency, transformation efficiency exhibited over a thousand times difference among the closely related Salmonella strains.
  
  
  CONCLUSIONS
  DNA acquisition efficiency is greatly variable among bacteria that have as high as over 99% identical genetic background, suggesting that bacterial speciation involves highly complex processes affected not only by whether beneficial exogenous DNA may exist in the environment but also the "readiness" of the bacteria to accept it.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Bao
authors.forename: Le
authors.initials: L
authors.lastname: Tang
authors.forename: Lu
authors.initials: L
authors.lastname: Yu
authors.forename: Xu-Yao
authors.initials: XY
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Xia
authors.initials: X
authors.lastname: Deng
authors.forename: Yong-Guo
authors.initials: YG
authors.lastname: Li
authors.forename: Ang
authors.initials: A
authors.lastname: Li
authors.forename: Da-Ling
authors.initials: DL
authors.lastname: Zhu
authors.forename: Randal N
authors.initials: RN
authors.lastname: Johnston
authors.affiliation: Genomics Research Center (one of The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), Harbin Medical University, 157 Baojian Road, Harbin 150081, China. grliu.natsumi@gmail.com.
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Liu
authors.forename: Ye
authors.initials: Y
authors.lastname: Feng
authors.forename: Shu-Lin
authors.initials: SL
authors.lastname: Liu
mesh_terms: D004247:DNA / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D049810:Genetic Speciation; D008969:Molecular Sequence Data; D011995:Recombination, Genetic; D012475:Salmonella / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014161:Transduction, Genetic; D014169:Transformation, Bacterial
chemical_list: D004269:DNA, Bacterial; D004247:DNA