Since DNA re-replication would inevitably lead to genome
instability, mechanisms to suppress re-replication as a means to prevent potentially harmful genome instabilities caused by re-replication would be beneficial to the cell. It has been addressed by a number of laboratories that cell-cycle checkpoint is activated when re-replication is induced. In S. cerevisiae, combining mutations in ORC, Cdc6, and MCM2–7 causes DNA re-replication and activates checkpoints