More information about the identity of community members can be obtained by hybridization analysis of
DGGE/TGGE patterns with taxon-specific oligonucleotide probes or with polynucleotide probes to hypervariable
regions of the 16s rRNA [lO,ll]. The latter probes are dioxigenin-labeled by enzymatic amplification of the rDNA of a
particular bacterial strain [lo] or the rDNA of excised TGGE bands [l l] using universal primers. These probes
are then used, under very stringent hybridization conditions to obtain enough specificity, in hybridization analysis of
DGGE/TGGE patterns. The advantage of this strategy is that no specific sequence information is needed to create
the probe. PCR-DGGE followed by hybridization analysis using genus- and cluster-specific oligonucleotide probes was
used to investigate the influence of soil pH on the composition of ammonia oxidizers [ 121.