The Physics of DNA Electrophoresis

Abstract

An area that has seen much fruitful collaboration between biologists and physicists in recent years is the development of the gel electrophoresis technique for separating DNA fragments. To some extent, the success achieved is due to the artificial nature of the system, which makes it more immediately amenable to theoretical treatment than most of the naturally occurring systems discussed in this Workshop, where the degree of complexity is far greater. The process involved here is straightforward and essentially physical - charged DNA molecules are forced to migrate through a gel by the application of an electric field - but it is of immense importance to biologists, as the efficient separation of different fragments is an inevitable requirement for the manipulation of DNA performed in molecular genetics, cancer research and, more recently, the human genome project. The physics turns out to be rather interesting, with a rich variety of dynamical behaviour displaying some unusual and unexpected features. More generally, gel electrophoresis is a good example of a driven diffusive system, many types of which are currently under investigation.