Agarose gel electrophoresis

Agarose gel electrophoresis is a method used in biochemistry, molecular biology, genetics, and clinical chemistry to separate a mixed population of DNA or proteins in a matrix of agarose, one of the two main components of agar. The proteins may be separated by charge and/or size (isoelectric focusing agarose gel electrophoresis is essentially size independent), and the DNA and RNA fragments by length. Biomolecules are separated by applying an electric field to move the charged molecules through an agarose matrix, and the biomolecules are separated by size in the agarose gel matrix.

Principle

Agarose gel electrophoresis works on the principle that many biological molecules are charged. Because of this, they will move in an electric field. The molecules to be separated (whether they are DNA, RNA, or protein) are loaded into wells in the agarose matrix. An electric current is applied across the gel so that one end of the gel has a positive charge and the other end has a negative charge.

Procedure

The procedure for agarose gel electrophoresis starts with the agarose being dissolved in a buffer solution. The solution is boiled until the agarose has completely dissolved. The solution is then cooled and poured into a casting tray. The gel is allowed to cool and solidify, and then is placed in an electrophoresis chamber. The DNA or protein sample is loaded into wells in the gel. Once the samples have been loaded, an electric current is applied. The negatively charged DNA or protein molecules move towards the positive electrode.

Applications

Agarose gel electrophoresis has a variety of applications such as in DNA fingerprinting, DNA forensics, DNA paternity testing, DNA cloning, and many other molecular biology or biochemistry applications.

See also

• Polyacrylamide gel electrophoresis
• Capillary electrophoresis
• Isoelectric focusing
• Two-dimensional gel electrophoresis