What technique did Hershey and Chase utilize to show that DNA was the genetic material?

Hershey and Chase conducted their landmark experiment using radioisotopes and bacteriophages to demonstrate that DNA is the genetic material. They designed their experiment by labeling the DNA of bacteriophages (viruses that infect bacteria) with radioactive phosphorus-32 and the protein coat with sulfur-35. After allowing the labeled viruses to infect bacterial cells, they used centrifugation to separate the cellular material from the phage coats.

The results showed that the radioactive phosphorus, marking the DNA, entered the bacterial cells while the sulfur-labeled protein remained outside. This indicated that DNA, not protein, was responsible for carrying and transmitting genetic information in the phages. The use of radioisotopes was crucial in tracking which component of the virus entered the bacterial cells. This experiment was a pivotal piece of evidence in establishing the role of DNA as the hereditary material.