FIG. 1.

Phylogenetic tree of the genus Bifidobacterium, computed on the basis of 16S rRNA gene sequences (a), ITS sequences (b), or concatenated sequences of the 16S rRNA gene and ITS (c). Bar scales indicate phylogenetic distances. Bootstrap values are reported for a total of 1,000 replicates. Trees were calculated by the neighbor-joining method as implemented in the neighbor module of PHYLIP. The trees were rooted using Nocardia farcinica. Shaded blocks indicate the different bifidobacterial phylogenetic clusters (53).