DGGE of cyanobacterial symbionts. 16S rDNA Denaturing Gradient Gel Electrophoresis of cyanobacterial symbionts occurring in sponges in this study. 1: Host = Spongia sp. Both high and low bands = Synechocystis sp., differing by 2 base pairs. 2: Host = Chondropsis sp. High band = uncultured phototrophic diatom. Low band = Oscillatoria spongeliae. 3: Host = Psammastra sp., symbiont = "Candidatus Synechococcus spongiarum". 4: Host = Chondrilla australiensis, symbiont = "Candidatus Synechococcus spongiarum". 5. Host = Chondropsis sp., symbiont = Oscillatoria spongeliae. 6. Host = Xestospongia sp. High band = uncultured sponge bacterium. Medium band not able to be sequenced, appearance matches Synechocystis. Low band = chloroplast. 7: Host = Mycale sp. 1 High (arrow) and middle bands = Synechocystis sp., 96.6% similarity to each other.