FIG. 3.

Phylogenetic tree indicating the relationship of deduced DsrAB amino acid sequences retrieved from Gessen Creek bank soils (indicated by bold type) to those of cultivated sulfate-reducing bacteria and other environmental clone sequences. The tree represents a consensus of the phylogeny determined using neighbor-joining, maximum-parsimony, and maximum-likelihood methods on an alignment of 245 amino acids of the dsrA gene product. Parsimony bootstrap values (1,000 data resamplings) of ≥90% are indicated by closed circles, and values of ≥70% are indicated by open circles. The scale bar indicates the estimated number of amino acid changes per amino acid sequence position.