Sequence divergences for orthologs shared across the ten bacterial genomes considered.

Values are comparable among genome pairs, since they are based the same set of orthologs. Dr and Dc values were estimated under the classification scheme of Miyata et al. [56]. Pre-filter values (columns 2–4) include 276 orthologs shared among the ten genomes considered. Filtered (columns 5–15) excludes orthologs for which Dr/Dc estimates are considered unreliable in any one of genome pairs i–v, generating a set of 256 shared orthologs. A less stringent filter was used for (vi) E.coli-Sal.typh., in order to retain a comparable number of genes for comparison (see footnote).
*The 221 genes analyzed for E. coli - S. typhimurium included the 256 orthologs analyzed for other genome pairs, minus 35 genes that contain zero radical and/or conservative substitutions between E. coli - S. typhimurium, thus making Dr/Dc zero or undefined. Application of the more stringent “high s.e. filter” to E.coli - Sal.typh. reduced this dataset to 119 genes, also summarized here.