Denaturing Gradient Gel Electrophoresis

Denaturing gradient gel electrophoresis (DGGE) is a powerful mutation detection technique described by Fisher et al. in 1983 (1 ). It allows the resolution of relatively large DNA fragments (usually polymerase chain reaction [PCR] products) differing by only a single nucleotide. DGGE is most frequently employed for the detection of unknown mutations. A related technique referred to as constant denaturing gradient gel electrophoresis (CDGE) is used for the sensitive detection of known mutations (2 ),(3 ). More recently a modified version of DGGE known as 2-dimensional DGGE has been employed for the simultaneous analysis of several PCR fragments (4 ). PCR fragments are initially separated by size on a polyacrylamide gel prior to loading onto a conventional denaturing gradient gel system, as will be described in this chapter.