Who isolated the first restriction endonucleases :

Options

A. Temin and Baltimore
B. Sanger
C. Nathan and Smith
D. Paul Berg

Answer

To solve the question "Who isolated the first restriction endonucleases?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the individuals or group who were responsible for isolating the first restriction endonucleases, which are enzymes that cut DNA at specific sequences.

2. **Evaluate the Options**:
- **Option 1: Temin and Baltimore**: They are known for their work on tumor cells and retroviruses, not for restriction endonucleases.
- **Option 2: Sanger**: He is famous for developing the DNA sequencing technique, but he did not isolate restriction endonucleases.
- **Option 3: Nathan and Smith**: This option refers to Daniel Nathan and Hamilton Smith, who, along with Werner Arber, were indeed involved in the discovery of restriction endonucleases.
- **Option 4: Paul Burke**: There is no significant association of Paul Burke with the isolation of restriction endonucleases.

3. **Identify the Correct Answer**: Based on the evaluation, the correct answer is **Option 3: Nathan and Smith**. They were awarded the Nobel Prize in 1978 for their contributions to the discovery of restriction endonucleases.

4. **Additional Information**: It is important to note that Werner Arber also played a significant role in this discovery, although he is not mentioned in the options.

### Final Answer:
The first restriction endonucleases were isolated by Nathan and Smith, along with Werner Arber.

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