Which experiment showed that DNA, rather than protein, is the hereditary material in bacteriophages?

The Hershey–Chase experiment showed that DNA, rather than protein, is the hereditary material in bacteriophages.

In 1952, Alfred Hershey and Martha Chase studied bacteriophage T2, a virus that infects Escherichia coli. They labeled viral DNA with radioactive phosphorus-32 and viral protein with radioactive sulfur-35. Phosphorus is present in DNA’s phosphate backbone, whereas sulfur occurs in certain proteins but not DNA.

After the labeled viruses infected bacteria, blending removed the empty viral coats. Most of the phosphorus-32 entered the bacterial cells and was found in progeny viruses; most of the sulfur-35 remained with the external coats. This indicated that DNA carried the instructions needed to produce new phages.

The result reinforced earlier work by Frederick Griffith and by Oswald Avery, Colin MacLeod, and Maclyn McCarty. It was influential evidence before the molecular structure of DNA was fully understood.