Figure 4
Neighbour-joining tree showing the relationship between representative OTUs of methanogenic culture clones (bold) and validated species of methanogens based on 16S rRNA gene sequences. The number of sequences in each OTU in each culture is listed in the right column. The OTU number corresponds to that listed in Supplementary Table S3 in the Supplementary Materials. The OTUs indicated by asterisks were also detected and abundant in the original formation waters. The dots indicate the bootstrap values above 70% in both the neighbour-joining and maximum likelihood trees. Methanococcus aeolicus (DQ195164) was used as an outgroup (data not shown). The scale bar represents 0.02 nucleotide substitutions per position.
