Figure 6.

Neighbor−joining tree based on 1737 amoA gene fragments (484 unambiguously aligned positions); only sequences from the work described here as well as selected reference sequences are shown. Representative amoA sequences for phylotype codes (OTUs) defined at 15% nucleotide sequence dissimilarity found in this study are indicated in large font. Phylotype codes are followed by names of representative clones of the amoA library and the accession number in brackets. Phylotypes which were only detected by microarray are shown as “Code (name of representative sequence, accession number, isolation source).” Reference sequences are described as “Name (accession number, isolation source).” nodes supported by maximum likelihood method are denoted with closed circles. Scale bar indicates an estimated sequence divergence of 7%. The outgroup is a thermophilic ammonia−oxidizing archaeal lineage containing Candidatus Nirosocaldus yellowstonii.