Repair mechanisms

1. Direct Repair - reversal or simple removal of the damage. 2. Mismatch repair - detection and repair of mismatched bases. 3. Excision repair - recognition of the damage followed by excision of a patch of DNA and its replacement by undamaged DNA. 4. Tolerance systems - allow DNA replication to proceed through damaged regions of DNA. 5. Retrieval systems - recombinational processes to repair damaged DNA.