Question

Name and explain the technique used for separating DNA fragments and making them available for biotechnology experiments.

Name and describe the technique that helps in the separation and isolation of DNA fragments.

Answer 1

Gel electrophoresis is a technique which is used for separating DNA fragments in a gel on the basis of their electric charge and size.

The process of gel electrophoresis is as follows:

• The fragments obtained after cutting with restriction enzymes are separated by using gel electrophoresis.

• Electric field is applied to the agarose gel matrix and the negatively-charged DNA fragments move towards the anode.

• Fragments separate according to their size by the sieving properties of agarose gel. The smaller the fragment, the farther it moves.

• Staining dyes such as ethidium bromide, upon exposure to UV radiation, are used to visualise the DNA fragments.

• DNA fragments are visible as bright orange-coloured bands in the agarose matrix.

• These bands are cut from the agarose gel and extracted from the gel piece (elution).​
• DNA fragments are purified and used in constructing recombinant DNAs