Figure 6. Left: PCR approach to amplification of 16s rRNA gene and adjacent internal transcribed spacer.  Center: Vertical section of 68°C Mushroom Spring mat with autofluorescence microscopy images of surface and deeper layers.  Right: Unrooted ITS phylogeny for cyanobacterial sequences of a single 16s rRNA type detected in the top layers (circles) or deeper layers (squares).