A multigene approach to phylogenetic analysis using the genus Mycobacterium as a model

1 UMR CNRS 5558, Laboratoire de bactériologie, Faculté de Médecine Lyon-Sud, BP 12, 69921 Oullins Cedex, France 2 Laboratoire de bactériologie, CHU Lyon Sud, 69495 Pierre-Bénite Cedex, France Correspondence G. Devulder devulder{at}biomserv.univ-lyon1.fr Advances in DNA sequencing and the increasing number of sequences available in databases have greatly enhanced the bacterial identification process. Several species within the genus Mycobacterium cause serious human and animal diseases. In order to assess their relative positions in the evolutionary process, four gene fragments, from the 16S rRNA (564 bp), hsp65 (420 bp), rpoB (396 bp) and sod (408 bp) genes, were sequenced from 97 strains, including all available type strains of the genus Mycobacterium . The results demonstrate that, in this case, the concatenation of different genes allows significant increases in the power of discrimination and the robustness of the phylogenetic tree. The sequential and/or combined use of sequences of several genes makes it possible to refine the phylogenetic approach and provides a molecular basis for accurate species identification. Published online ahead of print on 20 August 2004 as DOI 10.1099/ijs.0.63222-0. The GenBank/EMBL/DDBJ accession numbers for the sequences obtained in this study are listed in a supplementary table in IJSEM Online. Details of strains and sequence accession numbers and single-gene neighbour-joining trees for hsp65 , rpoB and sod and a maximum-likelihood tree for the combined dataset are available as supplementary material in IJSEM Online.