Electrophoresis Techniques That Are Useful in the Study of Genetics

Electrophoresis is a testing method in molecular biology for separating substances like proteins in order to study their molecular structure. Analyzing the molecular structure is done by measuring the rate of movement of the proteins through a gel material with the influence of an electrical field. Small molecular weight proteins move faster and the larger molecular weight proteins move slower on the grid. There are several types of electrophoresis including DNA, RNA and protein electrophoresis. All of these techniques can be useful in the study of genetics.

DNA Electrophoresis

• DNA is negatively charged due to the phosphate backbone of the double-stranded structure. The electrical potential will move towards the positive due to the negatively charged DNA. The rate at which the DNA travels to the positive end of the electrical potential is slowed by the agarose gel that contains the DNA. Larger molecules will travel slower and smaller molecules will travel faster. The gels are visualized under trans-illumination by staining the DNA with a fluorescent dye. This dye is usually ethidium bromide.

RNA Electrophoresis

• RNA is similar to DNA except that the sugar backbone of the molecule that is made up of ribose compared to deoxyribose in DNA. Denatured gels are used in RNA electrophoresis because the RNA tends to fold on itself and form secondary structures that are stable. This secondary structure prevents it from migrating according to size like in DNA electrophoresis. Including a RNA positive control will prevent skewed results or make easier to determine if something wrong with the RNA sample or gel. RNA markers can be used if molecular weight is known. The procedure is similar to that of DNA electrophoresis.

Protein Electrophoresis

• Protein electrophoresis is a test that measures different proteins in the blood. The bases of proteins are called amino acids. Proteins have different structures. Blood is taken from a vein through a needle that is attached to a collecting tube. The blood is then taken to lab and prepared on agarose gel in the same method as DNA electrophoresis. Blood proteins, including albumin and different types of globulin, are identified based on their molecular weight. The proteins travel according to size: the larger the size, the slower it will travel and the smaller the protein, the farther it will travel on the gel. Identifying blood proteins is useful in matching blood types among individuals.