The discovery that DNA, not protein, is the genetic material of the cell is attributed to Alfred Hershey and Martha Chase in their landmark 1952 experiment.

While other scientists had contributed to the understanding of genetics, Hershey and Chase definitively proved that DNA carries the genetic information. They used a clever experiment with bacteriophages (viruses that infect bacteria), labeling the DNA with radioactive phosphorus and the protein with radioactive sulfur. They then tracked which radioactive element was injected into bacteria by the phages. Their findings showed that the radioactive phosphorus (DNA) entered the bacteria, while the radioactive sulfur (protein) did not.

This experiment provided conclusive evidence that DNA, not protein, is the molecule responsible for carrying the genetic information.