Gel electrophoresis is a method to separate charged macromolecules (DNA, RNA, or proteins) of different sizes and to estimate their length.
Because nucleic acids are negatively charged ions at neutral or basic pH in an aqueous environment, this technique is often used to separate DNA or RNA molecules. This is necessary, for example, in the case of DNA profiling or to study RNA integrity. Proteins need to be denatured and given a negative charge before they can be analyzed with gel electrophoresis.
Gel electrophoresis is often used to separate PCR amplified DNA fragments. The process is also useful to isolate and extract DNA fragments of a specific size.
In the virtual lab we use the E-gel machine to perform gel electrophoresis (see image below).