Ethonal precipitation of DNA probes

1. Ethanol precipitation can be used to separate DNA from unincorporated nucleotides. When working with radiolabeled probes, proper protection and waste disposal are required.

2. Add 0.5 volumes of 7.5 M ammonium acetate and 2 volumes of cold ethanol (-20 C), vortex, centrifuge at 12,000 rpm for 30 minutes.

3. Remove supernatant, add 3 volumes cold 70% ethanol (-20 C), centrifuge at 12,000 rpm for 10 minutes.

4. Remove supernatant, air dry, and resuspend the probe in a suitable buffer.