[UV-light induction of "true" revertants to adenine independence in Bacillus subtilis cells]

The UV-irradiation of Bacillus subtilis Mu5u8u16 (met5 leu8 purA) induces with relatively high frequency the revertants to adenine independence (Ade+) which form the rapidly growing morphologically uniform colonies on the solid selective medium. The genetic analysis of a portion of UV-induced Ade+ revertants (crosses in transformation system) has cleared up that their DNA does not contain the original mutation ade16. This means that they arise as the result of "true" reversions. This reversion in purA gene can serve as a good model for the study of UV-induced mutagenesis in a proximal structural locus of Bac. subtilis chromosome.