Structural organization, amplification, deletion and rearrangements of DNA sequences associated with an unstable region of the chromosome of Streptomyces coelicolor A3(2).

The chromosome of Streptomyces coelicolor A3(2) carries unstable DNA sequences hybridising with DNA sequences from an unstable chromosomal region of the related species S. lividans. These S. coelicolor sequences are nearly identical to those of S. lividans TK23 in organisation but differ from those of S. lividans 66 TK64 which harbours a tandem duplication of these sequences. Southern hybridisations using heterologous probes and S. coelicolor DNA cleaved with a variety of restriction enzymes permitted us to construct a partial restriction map of the unstable region of the chromosome of S. coelicolor. Genetic analysis shows that the unstable region yields distinguishable variants with several distinct DNA rearrangements.