What role do restriction endonucleases play in Southern Blotting?

Restriction endonucleases play a crucial role in Southern Blotting by cutting DNA into smaller fragments. These enzymes are specific in their action, recognizing particular nucleotide sequences and cleaving the DNA at those sites. This fragmentation is essential in the Southern Blot technique, which involves the separation of DNA fragments by size through gel electrophoresis.

By cutting the DNA into defined lengths, restriction endonucleases enable researchers to analyze specific segments that may contain sequences of interest. Once the DNA has been fragmented, it is subjected to electrophoresis, allowing smaller fragments to travel through the gel more easily than larger ones. This separation based on size facilitates the subsequent steps in Southern Blotting, where transferred fragments can be probed for specific sequences.

The other roles mentioned in the options, such as amplifying DNA samples or visualizing DNA on a gel, are addressed by other techniques or tools in molecular biology, such as PCR (Polymerase Chain Reaction) for amplification and staining methods for visualization. Binding of DNA probes occurs later in the process after the fragments have been separated and transferred to a membrane, marking the final steps of blotting and further analysis.