Arrange the following steps in correct sequence for the technique of DNA fingerprinting.
(A). Detection of hybridized DNA fragments by autoradiography
(B). Separation of DNA fragments by electrophoresis
(C). Isolation and digestion of DNA
(D). Transferring of separated DNA fragments and hybridization using labelled VNTR probe
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (C), (B), (D), (A)
(C) Isolation and digestion of DNA — first. DNA is first taken out of the cells. Restriction endonucleases then cut it into fragments, which the later steps work on.
(B) Separation of DNA fragments by electrophoresis — second. The fragments are run on a gel. They separate according to their size.
(D) Transferring of separated DNA fragments and hybridization using labelled VNTR probe — third. The separated fragments are blotted onto a membrane of nitrocellulose or nylon. A labelled VNTR probe then pairs with the matching fragments.
(A) Detection of hybridized DNA fragments by autoradiography — last. Only fragments that have taken up the labelled probe can be detected. The X-ray film shows them as bands, the DNA fingerprint.
Note: A similar question was also asked in CUET (UG) 2026 on 07-06-2026 (Slot 2) and on 29-05-2026 (Slot 1).
NCERT Extract:
DNA Fingerprinting – …
