Question

Which of the following is not required for DNA fingerprinting?

• A. Southern blotting
• B. DNA-RNA hybridisation
• C. Restriction enzymes
• D. DNA-DNA hybridisation

Answer 1

The correct option is B DNA-RNA hybridisation

DNA fingerprinting involves identifying a person based on the unique repetitive sequences in their DNA. The DNA fingerprint of two individuals is different due to the variation in their genetic makeup, except for monozygotic twins.
The steps of DNA fingerprinting are as follows:

• Restriction enzymes are used in cleavage of DNA to create fragments of different sizes.
• The separated DNA fragments present in the gel are transferred to a nylon or nitrocellulose membrane, the process called southern blotting.
• DNA-DNA hybridisation is required for the identification of VNTR locus. DNA probes are the short sequences of minisatellite DNA which are then tagged with radioactive molecule. If the base pair sequences in the probe are complementary to the DNA sequences at the VNTR locus of the sample in study, then it gets hybridised and bands are generated after autoradiography.
• DNA-RNA hybridisation is not required for DNA fingerprinting as there is no RNA study involved here.