Question

Describe DNA fingerprinting technique in brief.

Hint:

Recall that VNTR variability, revealed via restriction digestion + gel electrophoresis + hybridisation, gives the unique pattern.

Answer 1

Step 1: Principle:
DNA fingerprinting is a technique that identifies differences in certain highly variable, repetitive DNA sequences (variable number tandem repeats, VNTRs) that are unique to every individual (except identical twins), even though most of the genome is identical between individuals.

Step 2: Procedure:
DNA is isolated from a sample (blood, hair root, etc.), cut into fragments using restriction endonucleases, separated by size using gel electrophoresis, and then hybridised (Southern blotting) with a labelled VNTR probe; this produces a unique pattern of bands — the 'DNA fingerprint' — specific to that individual.