Bacterial syntenies: an exact approach with gene quorum
1 INRIA Grenoble-Rhône-Alpes, team BAMBOO, 655 avenue de l'Europe,38334 Montbonnot Cedex, France
2 Université de Lyon, F-69000, Lyon; Université Lyon 1; CNRS, UMR5558, France
3 UMR754 INRA, Université de Lyon 1, 50 Avenue Tony Garnier, 69007 Lyon, France
BMC Bioinformatics 2011, 12:193 doi:10.1186/1471-2105-12-193Published: 24 May 2011
The automatic identification of syntenies across multiple species is a key step in comparative genomics that helps biologists shed light both on evolutionary and functional problems.
In this paper, we present a versatile tool to extract all syntenies from multiple bacterial species based on a clear-cut and very flexible definition of the synteny blocks that allows for gene quorum, partial gene correspondence, gaps, and a partial or total conservation of the gene order.
We apply this tool to two different kinds of studies. The first one is a search for functional gene associations. In this context, we compare our tool to a widely used heuristic - I-ADHORE - and show that at least up to ten genomes, the problem remains tractable with our exact definition and algorithm. The second application is linked to evolutionary studies: we verify in a multiple alignment setting that pairs of orthologs in synteny are more conserved than pairs outside, thus extending a previous pairwise study. We then show that this observation is in fact a function of the size of the synteny: the larger the block of synteny is, the more conserved the genes are.