DNA amplification and genetic instability in Streptomyces.

Genetic instability is very common in Streptomyces species, but only affects specific genes in any one strain. It sometimes occurs at high frequency spontaneously, but may be stimulated by treatments such as UV irradiation or intercalating agents. Deletion of genes occurs and may be accompanied by DNA amplifications. It is unlikely that there is plasmid involvement in most cases. Little is yet known about the molecular mechanisms of deletion and DNA amplification. Genetic instability can be a problem during commercial antibiotic production. DNA amplification of cloned genes is potentially useful for achieving both stability and high gene dosage.