DNA relatedness among verticil-forming Streptomyces species (formerly Streptoverticillium species)

Levels of DNA relatedness among 35 strains of Streptomyces species originally classified in the genus Streptoverticillium were determined spectrophotometrically. These strains represent eight of the phenotypic cluster groups described for the genus Streptoverticillium in Bergey's Manual of Systematic Bacteriology, Average linkage clustering of the DNA relatedness data resulted in 20 clusters including 13 single-member clusters, at a level of relatedness of >70%. Several species could be reduced to synonymy on the basis of DNA homology data, but these taxa were not generally equivalent to the clusters suggested by phenotypic numerical taxonomy data.