Replication origin under-licensing extends S phase and leads to mitotic entry before S-phase completion. At mitotic entry, M-CDKs phosphorylate DNA Pol, leading to its eviction from chromatin, which activates the DNA Damage Checkpoint. This provides time to complete DNA synthesis by MiDAS at the expense of genome stability. Pol1 and Pol12 phosphosites mapping was perfomed in cells entering mitosis following an extended S phase.