Figure 1: An example of a DGGE gel showing band compositions of various populations samples, representative of complex microbial ecosystems. Each band in each lane represents a 16S amplified product migrating to a unique position in the gel, which melts in a sequence dependant manner.
This separation is also aided considerably when a short sequence of G’s and C’s (about 40 nucleotides), often called GC-clamp, is attached to one end of the amplified DNA products (4, 6). This can be done by incorporation of this GC sequence into one of the primers used for amplifying the 16S rDNA fragments.
Conclusion
DGGE is undeniably a valuable approach in screening complex ecosystems on a large scale and in analyzing various environmental samples in a reduced amount of time. Using this technique, diagnosis of emerging infections could become easier and faster, and identification of uncultivable pathogens can also now be facilitated. Although there are limitations, DGGE is an interesting and unique approach that bridges many molecular biology tools together, and its limitations are primarily attributable to the fact that it is still a relatively new technique. If improved,