Ribosomal RNA and rDNA sequence analyses.

The potential of ribosomal (r) RNA and the encoding genes (rDNA) to elucidate natural relationships has been dramatically extended by improved sequencing approaches and the application of polymerase chain reaction. Sequence information on 16S and 23S rRNA/DNA from 69 strains of 53 Streptomyces species allows determination of regions that can be used as target sites for diagnostic probes, and for amplification and sequencing primers. To generate phylogenetic trees, sequence similarities are converted into distance values. The topologies of the trees based on different parts of the molecule are compared among each other and to the numerical phenotypic clustering of the strains.