What did Hershey and chase discover using radioactive labeling?

Hershey and Chase discovered that DNA, not protein, is the genetic material responsible for heredity. In their famous experiment with bacteriophages, they used radioactive labeling to distinguish between DNA and protein: they labeled DNA with phosphorus-32 and protein with sulfur-35. After allowing the viruses to infect bacteria, they found that only the radioactive DNA entered the bacterial cells, confirming that DNA carries the genetic instructions for the production of new viruses. This landmark discovery significantly advanced the understanding of genetics.