Using gel electrophoresis to produce real DNA fingerprints

One of the most intricate practicals to conduct in Year 13 is that of gel electrophoresis. It requires skill, patience and a steady hand, but rewards you with such a fantastic visual image of our genetic blueprint. Using a selection of restriction enzymes along with DNA samples from a bacteriophage, we were able to see the distinctive banding pattern made when DNA is cut into fragments. The enzymes cut DNA at specific sites along its length, producing fragments of genetic material that are all different sizes. When placed in a gel plate and an electric current passed through it, the fragments moved towards the positive terminal (as they were negatively charged). The smallest fragments moved the most. Staining the DNA with Azure allowed us to see the actual DNA in the plate. In lessons, we had learnt about the techniques of restriction mapping, southern blotting and gel electrophoresis, and so to conduct this experiment really helped to bring the Biology to life.