Denaturing gradient gel electrophoresis (DGGE) was introduced 20 years ago (1 ) as a gel system to separate DNA fragments. The seminal principle of this methodologic conquest was that DNA molecules were not separated according to size, as in conventional electrophoresis, but rather, according to base composition and sequence-related properties. Since then, the technology has been developed into a powerful, yet still challenging, method for detection of single base changes. In combination with polymerase chain reaction (PCR), it has been widely used by research and diagnostic laboratories in the analysis of cancer and inherited disease. The principles and potential applications of DGGE have been described in detail in a number of excellent reviews (2 –4 ) and are outlined only briefly in the following sections.
