Sequence network of Symbiodinium ITS2 types observed for each DGGE profile obtained from agariciid species. Ancestral Symbiodinium types C1 and C3 are represented by squares. Circle size is not representative of frequency. Dashed lines indicate sequence gaps (with gap size in number of base pairs). Colours group the different ITS2 sequences observed in each DGGE profile. The C3 type (indicated by black square) is found in all DGGE profiles except for P5.