Which of the following techniques can be used to introduce foreign DNA into cell ?

Options

A. Using disarmed pathogen
B. Microinjection
C. Gene gun
D. All of these

Answer

To answer the question "Which of the following techniques can be used to introduce foreign DNA into a cell?", we can analyze the methods mentioned in the video transcript step by step:

### Step-by-Step Solution:

1. **Understanding the Techniques**:
- We have three techniques mentioned: disarmed pathogen, micro-injection, and gene gun.

2. **Disarmed Pathogen**:
- This method involves using a modified pathogen that cannot cause disease (disarmed). When this pathogen infects a host cell, it can transfer recombinant DNA into that cell. This is a common method used in genetic engineering.

3. **Micro-Injection**:
- In this technique, recombinant DNA is directly injected into the nucleus of an animal cell using a fine needle. This method allows for precise introduction of DNA into the target cell and is widely used in transgenic animal production.

4. **Gene Gun**:
- The gene gun method, also known as the biolistic method, involves bombarding cells with high-velocity micro-particles (often made of gold or tungsten) that are coated with DNA. This method is effective for introducing DNA into plant cells and some animal cells.

5. **Conclusion**:
- All three methods mentioned (disarmed pathogen, micro-injection, and gene gun) are valid techniques for introducing foreign DNA into cells. Therefore, the correct answer to the question is "all of these."

### Final Answer:
The correct option is **4th: All of these**.

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