1. Run 5 mg of DNA to be labeled on an agarose gel.

2. Visulize the DNA under a UV light, cut out a slice of the gel containing the target DNA. Keep the volume of gel slice minimum.

3. Add 1 ml ddH₂O, melt the gel and denature DNA by boiling. Keep at 37 °C.

4. Prepare a reaction mix without the template. See DNA random labeling with 32P-dCTP.

5. Add 10 ml to the reaction mix. Proceed as has been described in DNA random labeling with 32P-dCTP.