The Advantages of Using Gel Electrophoresis

Gel electrophoresis is a process to separate strains of DNA by pushing it through a gel placed in a heated (and covered) table. The porousness of the gel causes larger fragments to separate first while smaller fragments continue through the gel. Since its first experimental use in the 1930's, gel electrophoresis has been refined through the use of different types of gel. Beginning with sucrose and then starch gels, DNA separation in electrophoresis greatly increased with modern use of agarose and acrylaminde gels. With the development of capillary electrophoresis, certain advantages and disadvantages have become clear for both methods.

Agarose Gel

• Agarose gel is easily poured for use and samples can be easily recovered. The gel is also highly modifiable to increase the separation between large and small DNA molecules. Since it is made from a sugar present in seaweed, agarose is cheaper than alternatives and a safer gel product for use in electrophoresis.

Acrylamide Gel

• Like agarose, acrylamide is easy to modify. With a higher load capacity, it can run more samples at the same. It's main advantage over agarose is that acrylamide has smaller pores, making it better suited for separating smaller DNA molecules that agarose gel would not be able to separate. However, bubbling is a greater problem for acrylamide, and, since acrylamide is a neurotoxin, it can be very dangerous to work with.

Capillary Electrophoresis

• Because heat dissipates quickly in the polymer, capillary electrophoresis takes less time than gels; minutes compared to hours. As well, since the results are monitored electronically the entire process can be automated. However, capillary electrophoresis can't run as many samples at the same time as gels, and the machines (priced at over $100,000 per unit) and reagents cost substantially more than the gel method of separation, so most labs do not have access to the technology.