A probe tagged DNA or RNA, allowed to hybridize with its complementary DNA, can be detected using:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Autoradiography
A probe is a short single-stranded DNA or RNA that has been tagged with a radioactive molecule. It sticks (hybridises) only to the DNA that is complementary to it. The place where it sticks is then shown on a photographic film.
(1) Autoradiography — Correct. The radioactive probe darkens the film where it has bound. This detects the hybridised DNA. A clone that carries a mutated gene does not bind the probe, so it does not appear on the film.
(2) Agarose gel electrophoresis — Incorrect. This separates DNA fragments by size. It does not detect a probe.
(3) Polymerase chain reaction — Incorrect. PCR makes many copies of a piece of DNA. It does not detect a probe.
(4) Centrifugation — Incorrect. This spins a sample to separate its parts by density.
NCERT Extract:
Molecular Diagnosis – …
