SPONTANEOUS RELEASE OF DNA IN SEQUENTIAL GENETIC ORDER BY BACILLUS SUBTILIS

The genetic activity of DNA spontaneously released during spore germination of Bacillus subtilis 168TT, was examined in a transformation system consisting of germinating spores as DNA donors and a differently marked transformable recipient. The results indicate a close correlation between DNA release and DNA synthesis. Genetic transformation using synchronously replicating germinating spores as DNA donors revealed that, in portions removed during germination, genetic markers appear extracellularly in an order similar to the known order of replication. The high relative marker frequencies obtained in transformation with released DNA allowed the construction of a genetic map often markers according to the marker frequency analysis described by Sueoka & Yoshikawa (1965) for extracted DNA. The map positions and order of replication of the various markers are in good agreement with those obtained by O'Sullivan & Sueoka (1967) and Dubnau, Goldthwaite, Smith & Marmur (1967) using density transfer experiments. © 1969.