title: The use of comparative genomic hybridization to characterize genome dynamics and diversity among the serotypes of Shigella.
abstract: BACKGROUND
  Compelling evidence indicates that Shigella species, the etiologic agents of bacillary dysentery, as well as enteroinvasive Escherichia coli, are derived from multiple origins of Escherichia coli and form a single pathovar. To further understand the genome diversity and virulence evolution of Shigella, comparative genomic hybridization microarray analysis was employed to compare the gene content of E. coli K-12 with those of 43 Shigella strains from all lineages.
  
  
  RESULTS
  For the 43 strains subjected to CGH microarray analyses, the common backbone of the Shigella genome was estimated to contain more than 1,900 open reading frames (ORFs), with a mean number of 726 undetectable ORFs. The mosaic distribution of absent regions indicated that insertions and/or deletions have led to the highly diversified genomes of pathogenic strains.
  
  
  CONCLUSIONS
  These results support the hypothesis that by gain and loss of functions, Shigella species became successful human pathogens through convergent evolution from diverse genomic backgrounds. Moreover, we also found many specific differences between different lineages, providing a window into understanding bacterial speciation and taxonomic relationships.
authors.affiliation: State Key Laboratory for Molecular Virology and Genetic Engineering, Chinese Center for Disease Control and Prevention, Beijing 100176, China. pengjp@gmail.com
authors.forename: Junping
authors.initials: J
authors.lastname: Peng
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: E
authors.initials: E
authors.lastname: Yang
authors.forename: Wen
authors.initials: W
authors.lastname: Bin
authors.forename: Candong
authors.initials: C
authors.lastname: Wei
authors.forename: Meisheng
authors.initials: M
authors.lastname: Sun
authors.forename: Qi
authors.initials: Q
authors.lastname: Jin
mesh_terms: D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics; D019143:Evolution, Molecular; D014644:Genetic Variation; D016680:Genome, Bacterial; D006801:Humans; D009693:Nucleic Acid Hybridization; D012703:Serotyping; D012760:Shigella / Q000235:genetics*; D014774:Virulence / Q000235:genetics
chemical_list: D004269:DNA, Bacterial