What did Hershey chase blender experiment help prove?

Hershey Chase's blender experiment was part of a series of experiments conducted in 1952 to determine whether DNA or protein was the genetic material. This became known as the Hershey-Chase experiment, after the two scientists who conducted it, Alfred Hershey and Martha Chase.

Background:

At that time, two ideas were proposed regarding the genetic material: The first suggested proteins, given their diversity and complexity, as the likely candidate for genetic information storage and transfer. Another idea was that an unknown substance called "nuclein," later known as nucleic acids, which consists of DNA and RNA, was responsible.

The Experiment:

1. Viral Labeling: Hershey and Chase used a virus that infects bacteria, known as a bacteriophage or phage for short. They grew bacterial cultures on a culture medium containing radioactive isotopes. In one set of experiments, they labeled viral proteins with radioactive sulfur-35, and in another set, they labeled viral DNA with radioactive phosphorus-32.

2. Centrifugation: The labeled phages were then allowed to infect bacteria. Next, the infected bacterial culture was blended for a short duration. This process sheared off the viral coats, along with any attached proteins, leaving only the DNA inside the bacterial cells.

3. Purification: The bacterial culture was then subjected to centrifugation to separate phage particles from the bacterial cells and any cellular debris. This process ensured that only intact bacterial cells remained, containing either labeled DNA or labeled protein, depending on the experimental setup.

4. DNA or Protein: The crucial question was: If DNA was the genetic material, it should be inside the bacterial cells after infection, while if protein were the genetic material, it should be found in the separated viral coats.

Results and Conclusion:

When testing for the presence of radioactive atoms, the researchers found significantly higher levels of radioactive phosphorus (DNA) within the bacterial cells compared to radioactive sulfur (protein). Moreover, minimal amounts of radioactive protein were detected within the cells.

This experiment strongly suggested that DNA, rather than protein, is the genetic material responsible for transmitting hereditary information.