Figure 1

Phylogenetic tree showing the position of Methanobacterium sp. BRM9 relative to type strains of other Methanobacterium species. The strains and their corresponding accession numbers are shown. The evolutionary history was inferred using the Neighbor-Joining method [14] with Methanothermus fervidus used as an outgroup. The optimal tree with the sum of branch length = 0.34833139 is shown. The percentage of replicate trees (>90%) in which the associated taxa clustered together in the bootstrap test (1000 replicates) are shown next to the branches [15]. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The evolutionary distances were computed using the Kimura 2-parameter method [16] and are in the units of the number of base substitutions per site. The analysis involved 19 nucleotide sequences. All positions containing gaps and missing data were eliminated. There were a total of 1168 positions in the final dataset. Evolutionary analyses were conducted in MEGA5 [17].