Nucleic acid carries genetic material (Hershey- Chase Experiment )

1. Nucleic Acid- Carries genetic material
Part-2
Hershey- Chase Experiment
Dr. Emasushan Minj
Assistant Professor
Department of Botany

2. Introduction
• Hershey-chase experiment was conducted in 1952, by Alfred
Hershey & Martha Chase using Phage and identified DNA to be the
genetic material.
• A phage is a virus that infects bacteria.
• It consists of a protein coat that encloses the dsDNA.
• Since phage consist only of nucleic acid surrounded by protein, it is
easy to determine whether the protein or the nucleic acid is the
genetic material.

3. Experiment-
• Radioactive isotopes of sulfur and phosphorus such as 35S and 32P
were used.
• T2- bacteriophage and the bacterium Escherichia coli were taken for
the experiment.
• The phages were labeled with radioactive isotopes 35S and 32P and
infect the bacterium growing in culture medium.
• Further to identify the material infected into the cell by phages
attached to the bacterial wall.

5. * E. coli was infected by 32P labeled DNA phage. 32P entered and next
generation of phages that burst from the infected bacterium results
significant amount of 32P label.
*E. coli was infected by 35S labeled protein coat phage. There was no
radioactive 35S in the next generation of phage.
*Experiment proved that genetic material in DNA not the protein.
• Hershey shared the 1969 Nobel Prize in Physiology or Medicine for
his discoveries concerning the genetic structure of virus.

6. Thank you