Unstable Genetic Elements Affecting Streptomycin Resistance in the Streptomycin-producing Organisms Streptomyces griseus NCIB 8506

There have been many cases in Streptomyces where a phenotype has proved to be unstable. This has usually been taken to suggest plasmid involvement. In the case of streptomycin resistance in two strains, this instability is reversible. Moreover, its cyclic nature suggests that insertion by a transposable element is affecting expression of a gene or genes