The use of comparative genomic hybridization to characterize genome dynamics and diversity among the serotypes of Shigella.
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.
Peng
Junping
J
State Key Laboratory for Molecular Virology and Genetic Engineering, Chinese Center for Disease Control and Prevention, Beijing 100176, China. pengjp@gmail.com
Zhang
Xiaobing
X
Yang
Jian
J
Wang
Jing
J
Yang
E
E
Bin
Wen
W
Wei
Candong
C
Sun
Meisheng
M
Jin
Qi
Q
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
D004269:DNA, Bacterial