FIG. 2.

Phylogenetic tree (maximum likelihood) for cyanobacteria and plastids based on publicly available, almost complete 16S rRNA genes from members of the cyanobacterial line. E. coli and B. subtilis were used as outgroups. The numbers next to the collapsed clusters indicate the number of sequences in each cluster. The 400-bp 16S rRNA sequences from our excised DGGE bands were placed phylogenetically by using parsimony criteria without changing the topology of the preestablished tree. The bar indicates 10% sequence divergence. The identities of strains correspond to the identities given in the databases, and we do not imply that they are necessarily taxonomically correct.