Circular Bacterial DNA (IMAGE) Rice University Caption This illustration of the replication cycle for circular bacterial DNA shows how Bacillus subtilis bacteria use the ratio of proteins KinA to Spo0F to time their decision to form spores. By copying the gene for Spo0F (purple) early in the cell-division cycle and the gene for KinA (green) later in the cycle, the bacteria assure that the decision to form a spore or divide is made when DNA replication has completed. Credit L. Huang/Rice University Usage Restrictions For news reporting purposes only. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.