5'-16S rDNA based phylogenetic tree of the genus Mycobacterium, including one representative strain of each sequence variant (sequevar = sqv.). T designates the type strain of this species. Multiple sequence alignments were determined using the CLUSTAL W algorithm in the MegAlign component of the Lasergene program. The tree was rooted using Corynebacterium pseudodiphtheriticum as the outgroup sequence. Sequences were all determined in our laboratory unless indicated by GenBank accession number. Species having identical sequences are shown in bold. The numbers on the abscissa represent the percent distance between different isolates.