Bio-Rad DCode™ Universal Mutation Detection System - Manual (Page 40)

Fig. 4.20. Pouring a CDGE gel.
4. Pour or pipette the gel solution into the sandwich until the gel solution covers the wells of
the comb. Straighten the comb to the desired well depth. Add more gel solution if needed.
5. Allow the gel to polymerize for about 60 minutes. After polymerization, remove the comb
by pulling it straight up slowly and gently.
6. Continue with Section 8 for electrophoresis.
4.3 Introduction to Temporal Temperature Gradient Gel
Electrophoresis (TTGE)
Temporal Temperature Gradient Gel Electrophoresis 14,15 (TTGE) exploits the principle on
which DGGE is based, without requiring a chemical denaturing gradient. Amplified mutant and
wild-type DNA from the gene of interest is loaded onto a polyacrylamide gel containing a
constant concentration of urea. During electrophoresis, the temperature is increased gradually
and uniformly. The result is a linear temperature gradient over the length of the electrophoresis
run. Thus, a denaturing environment is formed by the constant concentration of urea in the gel
in combination with the temporal temperature gradient. With no chemical gradient required,
rapid, high-throughput screening is possible.
The DCode system allows precise control of the temperature ramp rate measured in °C per
hour. Control over the temperature range and ramp rate allows optimum denaturing conditions.
An example of a TTGE gel is shown in Figure 4.21.
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