Southern blotting.

This video explains the principles of Southern Blotting, a laboratory technique used to achieve a permanent visible picture of bands of DNA fragments. Southern blotting follows the step by step process from separation, through to fixing and to the final visualising of the DNA fragments as bands on a photographic film. The video charts the progress of the experiment to compare DNA samples from the individuals, one normal and four with a neurological disease. Professor Alan Lehmann from the MRC Cell Mutation Unit at the University of Sussex summarises the final autoradiogram. This is followed by a short description of the Northern Blotting process, a similar technique for RNA fragments.