Question #16740
1 Answer
Radioactive DNA is DNA that has been made radioactive by incorporating a nucleotide that contains a radioactive element, usually Phosphorus-32. This makes the DNA easier to "see".
Explanation:
Techniques like Southern Blot usually utilize a DNA probe, and frequently this probe is made radioactive so it is easier to "see". The DNA is synthesized using radiolabelled NTPs. For example, the alpha phosphorus of ATP is made radioactive, and when this nucleotide is used in the synthesis, the probe is radioactive. P-32 is frequently used because it has a short half-life (about 2 weeks) and is a simple beta-emitter.
The probe is added to the gel and after annealing, photographic film is placed against the gel. After exposure, the film is developed, and the location of the probe (and target DNA) can be visualized with respect to a ladder.
