The unequivocal proof that DNA is the genetic material came from the experiments of-
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Alfred Hershey and Martha Chase
Hershey and Chase (1952) grew bacteriophages with radioactive phosphorus (in DNA) or radioactive sulphur (in protein). Only the radioactive DNA entered the bacteria and appeared in the new phages, so DNA is the genetic material, not protein.
Option (1) Colin MacLeod and Maclyn McCarty — Incorrect. With Oswald Avery they showed that DNA is the transforming principle in Griffith’s experiment, but not all biologists were convinced.
Option (2) Frederick Griffith — Incorrect. He discovered transformation in Streptococcus pneumoniae, without knowing what the transforming material was.
Option (3) Matthew Meselson and Franklin Stahl — Incorrect. Using 15N and 14N in E. coli, they proved that DNA replicates semi-conservatively. Their work showed how DNA copies itself, not whether DNA is the genetic material.
Option (4) Alfred Hershey and Martha Chase — Correct. Alfred Hershey and Martha Chase (1952) grew bacteriophages with radioactive phosphorus or sulphur. Only the radioactive DNA entered the bacteria, giving the unequivocal proof that DNA is the genetic material.
Note: A similar question was also asked in CUET (UG) 2025 on 27-05-2025 (Slot 2) and on 16-05-2025 (Slot 1).
NCERT Extract:
The Genetic Material Is DNA – …
