Alfred Hershey And Martha Chase Experiment

The Hershey and chase experiment conclusively proved that DNA was the genetic material. Alfred Hershey and his lab technician Martha Chase carried out this experiment. The discovery began when Alfred Hershey believed that proteins were more likely to carry genetic material than was the simple DNA molecule. They decided to track the transfer of protein DNA between a virus and its host by the T2 bacteriophage as the vehicle for delivering genetic material. To reproduce, the bacteriophage injects its genetic material into the bacterium and leaves its protein shell attached to the host. The virus then takes control of the bacterium’s reproductive systems and duplicates itself, destroying the host. Although it was already known that the protein shell remained outside of the bacterium, researchers believed it possible that, upon attachment, certain proteins were transferred from the virus to the bacteria. If
This enabled Hershey and Chase to track the location of the DNA and protein according to the radiation concentrations. Once tagged they were introduced and infected E. coli. They then used a blender to violently disturb the infected bacteria resulting in the shells of the protein to detach from their host. A centrifuge was used next in order to separate the bacterium from the phages and protein. After completion, the radiation concentrations of E. coli and the protein shells were measured. The results showed that there were large quantities of the phosphorus tracer only in the bacterial sample, demonstrating that DNA was transferred from the bacteriophage to the host organism. Further to this, despite the protein shells being detached while phage reproduction, the virus was copied in each of the host cells, suggesting that the protein shell was not required for the replication process following the initial insertion of genetic material (scarc,