Which of the following is used in recombinant DNA technique ?

Options

A. Cell wall of virus
B. Gene which produces capsid of virus
C. Virus
D. Capsid of virus

Answer

**Step-by-Step Text Solution:**

1. **Understanding Recombinant DNA Technology**: Recombinant DNA technology involves combining DNA from different sources to create a new genetic combination. This technique is widely used in genetic engineering.

2. **Identifying the Options**: The question provides four options:
- Cell wall of virus
- Gene which produces capsid of virus
- Virus
- Capsid of virus

3. **Analyzing Each Option**:
- **Cell wall of virus**: Viruses do not have a cell wall; they have a protein coat (capsid) that protects their genetic material. Therefore, this option is incorrect.
- **Gene which produces capsid of virus**: While this gene is important for the virus's structure, it is not directly used as a vector in recombinant DNA technology. Thus, this option is not the best choice.
- **Virus**: Viruses can be used as vectors to introduce foreign DNA into host cells. They can carry the gene of interest into the host organism, making this option a strong candidate.
- **Capsid of virus**: The capsid is the protein shell of the virus, but it does not serve the function of carrying genetic material into host cells. Therefore, this option is also incorrect.

4. **Conclusion**: The best answer is "Virus" because viruses are often used as cloning vectors in recombinant DNA technology. They can effectively deliver the gene of interest into host cells, leading to the creation of recombinant or transgenic organisms.

**Final Answer**: Virus

---