16S rRNA-based phylogeny of sponge-associated cyanobacteria and chloroplasts. 16S rRNA-based phylogeny of sponge-associated cyanobacteria and chloroplasts. Sponge-derived sequences are shown in bold. The displayed tree is a maximum likelihood tree constructed based on long (≥1,000 nucleotides) sequences only. Shorter sequences were added using the parsimony interactive tool in ARB and are indicated by dashed lines. Shaded boxes represent sponge-specific monophyletic clusters, as defined by Hentschel et al. (146), i.e., a group of at least three sponge-derived 16S rRNA gene sequences which (i) are more similar to each other than to sequences from other, nonsponge sources, (ii) are found in at least two host sponge species and/or in the same host species but from different geographic locations, and (iii) cluster together irrespective of the phylogeny inference method used (all clusters shown here also occurred in neighbor-joining and maximum parsimony analyses). Names outside wedges of grouped sequences represent the sponges from which the relevant sequences were derived; the number in parentheses indicates the number of sequences in that wedge. Filled circles indicate bootstrap support (maximum parsimony, with 100 resamplings) of ≥90%, and open circles represent ≥75% support. The outgroup (not shown) consisted of a range of sequences representing several other bacterial phyla. Bar, 10% sequence divergence. Michael W. Taylor et al. Microbiol. Mol. Biol. Rev. 2007; doi:10.1128/MMBR.00040-06