FIG. 6.

Maximum-likelihood phylogenetic tree of 16S rRNA clones within the α subgroup (A) and the β, γ, and δ subgroups (B) of the Proteobacteria division. Winter clones begin with W, spring clones with P, and summer clones with S. Cultured bacterial isolates from the alpine begin with DL. Other sequences are from GenBank. Sequences occurring more than once are indicated with an asterisk (Table 2).