RC341. In all cases, phylogenies inferred by the ORFs were incongruent with species phylogeny (see Additional files 16, 17, and 19). Our data suggests that V. cholerae VL426 (V. cholerae biotype albensis) received a VSP-I similar to that of Vibrio sp. RC341 and Vibrio sp. RC586 via horizontal gene transfer. We also found evidence of horizontal

transfer of V. cholerae GI-2 from V. cholerae to Vibrio sp. RC586, as well as Vibrio sp. RC341 Islet-3 and V. cholerae GI-4 from Vibrio sp. RC341 to V. cholerae strains. VSP-II, islets-2, -4, -5, and GIs-1, -2, -3, -9, -10, all present in at least one V. cholerae genome and in Vibrio sp. RC341, showed no evidence of horizontal gene transfer. Most likely there are many undescribed variants of these elements, in both structure and nucleotide sequence, yet to be found in the

natural environment, with certain variants more SB525334 concentration frequently transferred Cyclosporin A mw among strains of the same species. Coevolution of the island and host genome over time no doubt occurs. In any case, based on the data reported here V. cholerae is not alone in propagating these elements. They surely cycle among different but closely related species in the environment. Unique Genomic Islands Vibrio sp. RC586 putatively encodes five unique genomic islands and islets not yet reported for V. cholerae (see Additional files 12 and 13). Vibrio sp. RC586 GI-2 and islet-5 encode phage-like elements. Interestingly, islet-5 is annotated as probable coat protein A precursor, with similarity to bacteriophage f237 ORF5 of V. campbellii and zona occludens toxin (zot), with high similarity to V. parahaemolyticus and V. harveyi zot (VOA_001598-VOA_001600). This phage-like element is inserted at the homologous locus for V. cholerae O1 Classical CTXΦ insertion (VCA0569-VCA0570). Vibrio sp. RC586 GI-4 encodes sequences homologous to the Tn7 transposition tnsABCDE, a transposon known to integrate into phylogenetically diverse organisms and form Rolziracetam genomic islands [36]. Vibrio sp. RC586 GIs-1, -3, -4, and islets-1 through 6 all share homologous insertion loci with previously described

V. cholerae GIs (see Additional file 12). Vibrio sp. RC341 encodes six putative unique genomic islands not reported before (see Additional files 11 and 13). Vibrio sp. RC341 GIs-1, 2, 3, 4, and 7 all encode phage-like/related elements. Vibrio sp. RC341 GI-4 and 7 both encode several transposases and a Selleck NSC 683864 sequence with homology to an insertion-like sequence in the V. parahaemolyticus insertion sequence element ISV-3L. Vibrio sp. RC341 GI-6 (VCJ_002614 to VCJ002618), ca. 4962 bp region of hypothetical proteins and transposases, is inserted at the homologous locus for V. cholerae O1 Classical CTXΦ, a locus shown to harbor a variety of GIs and phages [17] (see Additional file 11). Conclusions The genomes of two new Vibrio species previously characterized as variant V. cholerae, have been sequenced and their sequences used to describe their interesting and important features.