Agar gel electrophoresis

Agar 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

Agar gel electrophoresis works on the principle that charged particles will migrate in an electric field. The particles, such as DNA fragments, will migrate towards the positive pole of the electric field. The rate of migration of the particles is inversely proportional to their size, meaning that smaller particles will migrate faster than larger ones.

Procedure

The procedure for agar gel electrophoresis starts with the preparation of the agar gel. This is done by dissolving agarose powder in a buffer solution, which is then heated until the agarose is completely dissolved. This solution is then poured into a casting tray, where it is allowed to cool and solidify.

Once the gel has solidified, the sample of DNA or protein is loaded into wells in the gel. An electric current is then applied across the gel, causing the DNA or protein molecules to move through the gel. The smaller molecules will move faster and therefore further than the larger ones.

After the electrophoresis is complete, the gel can be stained to visualize the separated DNA or protein molecules. The most common staining techniques involve the use of ethidium bromide for DNA and Coomassie Brilliant Blue for proteins.

Applications

Agar gel electrophoresis has a wide range of applications in scientific research. It is used in DNA fingerprinting, DNA paternity testing, DNA cloning, and many other areas of molecular biology and biochemistry.