FIG. 1.

Distance neighbor-joining trees of the betaproteobacterial AOB 16S rRNA based on (A) a subset of cloned sequences based on the 1,060-bp fragment or (B) the 295-bp fragment. Database sequences for cultured strains and environmental sequences are in boldface and are identified by GenBank accession numbers. Monterey Bay sequences are labeled as month-year-depth (surface [S], mid [M], or deep [D])-clone number; e.g., 10-99-S-18 represents October 1999 surface clone 18. Bootstrap values of >50 are displayed.