How would Hershey and Chase learn whether genes were made of proteins?

Hershey and Chase conducted their famous experiment using bacteriophages, which are viruses that infect bacteria. They labeled the protein coat of the phage with radioactive sulfur and the DNA with radioactive phosphorus. By allowing the labeled phages to infect bacteria and then separating the viral coats from the bacterial cells, they observed that only the phosphorus-labeled DNA entered the bacteria, while the sulfur-labeled protein remained outside. This provided strong evidence that genes are made of DNA, not proteins.