Inferring the evolutionary history of vibrios by means of multilocus sequence analysis

Laboratory of Microbiology, Faculty of Fisheries, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan; Ocean Research Institute, University of Tokyo, 1-15 Minamindai, Nakano-ku, Tokyo, 164-8639, Japan; Department of Genetics, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Ilha do Fundão, Caixa Postal 68011, CEP 21944-970, RJ, RJ, Brazil

^* To whom correspondence should be addressed. Email: sawabe{at}fish.hokudai.ac.jp.

	Abstract

We performed the first broad study aiming at the reconstruction of the evolutionary history of vibrios by means of multilocus sequence analysis of nine genes. Overall, 14 distinct clades were recognized using the Splits Tree Decomposition method. Some of these clades may correspond to families, e.g. the clades Salinivibrio and Photobacteria, while other clades, e.g. Splendidus and Harveyi, correspond to genera. The common ancestor of all vibrios was estimated to have been present 600 million years ago. We can define species of vibrios as groups of strains that share > 95% gene sequence similarity and >99.4 % AAI based on the 8 protein coding house keeping genes. The gene sequence data was used to refine the standard online electronic taxonomy of vibrios scheme (http://www.taxvibrio.lncc.br).