Arrange the given steps which are involved in DNA fingerprinting in correct sequence.
(A) Digestion of DNA by restriction endonucleases
(B) Hybridization using a labelled VNTR probe
(C) Detection of hybridized DNA fragments by autoradiography
(D) Separation of DNA fragments by electrophoresis
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (D), (B), (C)
(A) Digestion of DNA by restriction endonucleases — first of the given steps. After the DNA is isolated, restriction enzymes cut it into many fragments of different lengths.
(D) Separation of DNA fragments by electrophoresis — second. In gel electrophoresis the fragments move through the gel and get separated according to their size. The separated fragments are then transferred (blotted) onto a membrane of nitrocellulose or nylon.
(B) Hybridization using a labelled VNTR probe — third. A labelled VNTR probe is added to the membrane. It pairs (hybridises) only with the DNA fragments that carry the matching repeat sequence.
(C) Detection of hybridized DNA fragments by autoradiography — last. The radioactive label on the probe exposes an X-ray film. The dark bands on the film form the DNA fingerprint.
Note: A similar question was also asked in CUET (UG) 2026 on 29-05-2026 (Slot 1), in CUET (UG) 2025 on 22-05-2025 (Slot 2), in CUET (UG) 2024 on 29-05-2024 (Slot 1), and in CUET (UG) 2023 on 11-06-2023 (Slot 3).
NCERT Extract:
DNA Fingerprinting – …
