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

Abstract

Advances in DNA sequencing and the increasing number of sequences available in databases have greatly enhanced the bacterial identification process. Several species within the genusMycobacteriumcause 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) andsod(408 bp) genes, were sequenced from 97 strains, including all available type strains of the genusMycobacterium. 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.