Practical gel electrophoresis applications include typing bacteria, tracking the sources and spread of disease, monitoring bacterial evolution for vaccine design and confirming an identity in forensic cases. Gel electrophoresis spans a broad range of industries such as pharmacology, cancer research, mining and brewing.
Gel electrophoresis entails passing an electrical charge through a porous material after applying a solution containing the targeted substance. DNA, RNA, and proteins require different extraction, gel makeup, and buffering methods. Electrophoresis exploits the fact that shorter strands travel through a gel medium at higher speeds, separating out different molecules. Staining picks out the individual strands for identification. Edward M. Southern developed a technique to transfer the results of gel electrophoresis to a membrane, preserving the relative positions of the molecules for further research. Southern Blotting for DNA inspired Northern Blotting for RNA and Western Blotting for protein. A further refinement uses charged Nylon membranes to ensure durable and reusable results.Other types of molecular identification supplant gel electrophoresis when conditions require different approaches. Capillary electrophoresis increases sensitivity to smaller particles at the expense of less consistent readings. Peptide nucleic acid (PNA) analysis combines a surface probe and reporter probe allowing for fast anthrax DNA and HIV RNA identification in the field.