Restriction modification system

The restriction-modification (R-M) system is a biological mechanism found in many bacteria and archaea that serves as a defense against foreign DNA, such as that from viruses (bacteriophages) or plasmids. The system is composed of two main components: 1. **Restriction Enzymes (Restriction endonucleases)**: These enzymes scan DNA for specific sequences (restriction sites) and cut the DNA at or near these sites.