DNA Gel Electrophoresis

Abstract

The development of gel electrophoresis as a method of separating and analyzing DNA has been one of the forces driving the revolution in molecular biology for the last 20 years. In principle, DNA gel electrophoresis is conceptually easy to understand and technically easy to execute. In practice, there are a lot of small details that affect the accuracy and reproducibility of the results. This chapter presents a detailed description of the experimental methods used for DNA gel electrophoresis, designed as a guide for the investigator with little or no experience with this technique. The methods described here are those used every day in the author’s laboratory; additional protocols and ancillary techniques may be found in Sambrook et al. (1987). All discussions refer to the separation of double-stranded DNA molecules in slab gels, using unidirectional electric fields and fluorescent detection methods. The pulsed field gel electrophoresis (PFGE) of large DNA molecules (Birren and Lai 1993) and DNA capillary electrophoresis (Righetti and Gelfi 1996) are described in detail elsewhere.