Fig 1.

Phylogenetic relationship of F. prausnitzii isolates to other members of Clostridium cluster IV (Ruminococcaceae) based on 16S rRNA gene sequences. The tree was constructed using the ARB software package using the neighbor-joining method for distance analysis (Jukes-Cantor algorithm) with 1,533 informative positions considered (61 to 1,442 by E. coli 16S rRNA gene numbering). Bootstrap values above 80% (expressed as a percentage of 1,000 replications) are shown at branching points. Solid circles indicate branches that were consistent with calculations obtained by maximum-parsimony method. Empty circles represent those branches consistent with the maximum likelihood. The scale bar indicates the number of substitutions per site. F. prausnitzii isolates incorporated in this study are highlighted in bold. Sequence accession numbers are shown in parentheses. The database sequence for ATCC 27766 was included, but this strain was not studied here and it is not listed in Table 1.