Denaturing gradient gel electrophoresis (DGGE)

The DGGE method relies on the fact that double-stranded
DNA molecules have specific denaturation characteristics, i.e.
conditions at which the double-stranded DNA disassociates into
its two single-stranded units. The denaturation of the DNA
strands can be achieved by increasing temperature or by the
addition of a chemical denaturant such as urea or formamide.
If a PCR product contains a mutation, this will subtly modify
the conditions at which denaturation occurs, which in turn
affects its electrophoretic mobility. In DGGE, a gradient of the
denaturing agent is set up so that the PCR products migrate
through the denaturant and are separated based on their
sequence specific mobility.