DNA is genetic material was proved by

Options

A. Watson and Crick
B. Hershey and Chase
C. Griffith
D. Sutton and Boveri

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks who proved that DNA is the genetic material. This is a fundamental concept in molecular biology.

2. **Identifying Key Scientists**: The options provided include Watson and Crick, Hershey and Chase, Griffith, and Sutton and Bovary. Each of these scientists contributed to our understanding of genetics in different ways.

3. **Focusing on Hershey and Chase**: Among the scientists listed, Hershey and Chase are known for their pivotal experiment that demonstrated DNA as the genetic material. Their work involved bacteriophages, which are viruses that infect bacteria.

4. **Describing the Experiment**: Hershey and Chase conducted an experiment using two different isotopes to label the components of the bacteriophage:
- They used **Sulfur-35 (S-35)** to label the protein coat of the bacteriophage.
- They used **Phosphorus-32 (P-32)** to label the DNA, as phosphorus is a component of DNA nucleotides.

5. **Conducting the Infection**: The labeled bacteriophages were allowed to infect bacterial cells. After the infection, the mixture was blended to separate the phage coats from the bacterial cells.

6. **Centrifugation**: The blended mixture was then centrifuged. This process separates components based on their density. The heavier bacterial cells formed a pellet at the bottom, while the lighter phage coats remained in the supernatant.

7. **Analyzing Results**: Upon analyzing the pellet, Hershey and Chase found that only the phosphorus (from the DNA) was present in the bacterial cells, while the sulfur (from the protein) was not. This indicated that only the DNA had entered the bacterial cells and was responsible for carrying genetic information.

8. **Conclusion**: The results of the experiment led to the conclusion that DNA is the genetic material, as it was the only component that was transferred into the bacteria during the infection.

9. **Final Answer**: Therefore, the correct answer to the question is that DNA as genetic material was proved by **Hershey and Chase**.

---