Open Access Open Badges Research article

Systematic determination of the mosaic structure of bacterial genomes: species backbone versus strain-specific loops

H Chiapello1*, I Bourgait1, F Sourivong1, G Heuclin1, A Gendrault-Jacquemard1, M-A Petit2 and M El Karoui2

Author Affiliations

1 Mathématique, Informatique & Génome, INRA Domaine de Vilvert, 78352 Jouy-en-Josas cedex, France

2 Unité de Recherches Laitières et Génétique Appliquée, INRA Domaine de Vilvert, 78352 Jouy-en-Josas cedex, France

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BMC Bioinformatics 2005, 6:171  doi:10.1186/1471-2105-6-171

Published: 12 July 2005



Public databases now contain multitude of complete bacterial genomes, including several genomes of the same species. The available data offers new opportunities to address questions about bacterial genome evolution, a task that requires reliable fine comparison data of closely related genomes. Recent analyses have shown, using pairwise whole genome alignments, that it is possible to segment bacterial genomes into a common conserved backbone and strain-specific sequences called loops.


Here, we generalize this approach and propose a strategy that allows systematic and non-biased genome segmentation based on multiple genome alignments. Segmentation analyses, as applied to 13 different bacterial species, confirmed the feasibility of our approach to discern the 'mosaic' organization of bacterial genomes. Segmentation results are available through a Web interface permitting functional analysis, extraction and visualization of the backbone/loops structure of documented genomes. To illustrate the potential of this approach, we performed a precise analysis of the mosaic organization of three E. coli strains and functional characterization of the loops.


The segmentation results including the backbone/loops structure of 13 bacterial species genomes are new and available for use by the scientific community at the URL: webcite.