FIG. 4.

Neighbor-joining phylogenetic trees of the 16S rRNA gene sequences from groups involved in methane, ethane, or propane oxidation, based on their abundance in both the heavy DNA clone libraries and the heavy T-RFLP fractions, relative to light DNA and ¹²C controls. (A) Gammaproteobacteria; (B) Betaproteobacteria. Sequences from this study are shown in bold, with predicted MspI T-RF lengths in parentheses. Reference sequences from GenBank are shown with accession numbers in parentheses. Filled circles indicate bootstrap values above 90% and open circles bootstrap values above 50% (2,000 replicates).