Identify the correct sequence involved in technique of DNA fingerprinting?
(A) Hybridisation using labelled VNTR probe, and detection of hybridised DNA fragments by autoradiography
(B) Separation of DNA fragments by electrophoresis
(C) Transferring of separated DNA fragments to synthetic membranes, such as nitrocellulose or nylon
(D) Isolation and digestion of DNA by restriction endonucleases
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (D), (B), (C), (A)
(D) Isolation and digestion of DNA by restriction endonucleases — first. DNA is first taken out of the cells, for example from a drop of blood or a hair root. Restriction enzymes then cut it into fragments of different sizes.
(B) Separation of DNA fragments by electrophoresis — second. The fragments are run on an agarose gel, which sorts them by size.
(C) Transferring of separated DNA fragments to synthetic membranes, such as nitrocellulose or nylon — third. This is blotting. The sorted fragments are moved from the gel onto a membrane in the same pattern, so that they can be handled and probed.
(A) Hybridisation using labelled VNTR probe, and detection of hybridised DNA fragments by autoradiography — last. The labelled probe binds only to the fragments that carry the VNTR. Autoradiography then shows them as bands on a film. The band pattern differs from person to person.
Note: A similar question was also asked in CUET (UG) 2026 on 29-05-2026 (Slot 1).
NCERT Extract:
DNA Fingerprinting – …
