Hershey-Chase experiment

Video https://www.youtube.com/watch?v=hubXqPrslR4

Figure 7.2 https://simple.wikipedia.org/wiki/Hershey%E2%80%93Chase_experiment#/media/File:HersheyChaseEx.png

The experiment showed that DNA was the genetic material of life. Many thought that proteins were where the genetic information was carried.

Hershey and Chase used a virus which infects bacteria. These are called bacteriophages. The one they used was called T2 phage. It only contains DNA wrapped in a simple protein coat. They used a very well understood bacteria Escherichia coli for their experiments. The phage infects the bacteria by injecting its genetic material into it.

In stage 1 they labelled the DNA of a virus with radioactive Phosophorous-32

In stage 2 they labelled the protein coat of the virus with a different radioactive isotope Sulfur-35.

In each experiment the phages were separated from the bacteria by the shaking of the blender then the proteins in the phages were separated from the cells by centrifuging. The proteins are found in the supernatant solution whereas the bacterial cells are in a pellet at the bottom of the centrifuge tube.

The results shown in the diagram Figure 7.2 led them to conclude that DNA carried the genetic information.