Question

Name and describe the technique that helps in separating the DNA fragments formed by the use of restriction endonuclease

Answer 1

Gel electrophoresis is a technique of separating DNA fragments formed by the action of restriction endonucleases.

The fragments of DNA are placed in a typical agarose gel under an electric field. The DNA fragments move towards the anode as these fragments are negatively charged molecules. The DNA fragments separate according to their size through the sieving effect provided by the agarose gel. The smaller the fragment size, the farther it moves. The separated DNA fragments are stained with ethidium bromide followed by exposure to ultraviolet radiation. The DNA fragments are seen as orangecoloured and are cut out from the agarose gel and extracted from the gel piece. This step is called elution.