Which of the following site/s must be present in any suit- able vector for genetic engineering?

Options

A. Ori site
B. Restriction site
C. Marker site
D. All of these

Answer

To answer the question regarding which sites must be present in any suitable vector for genetic engineering, we can break down the necessary components as follows:

### Step-by-Step Solution:

1. **Identify the Components of a Suitable Vector**:
- A suitable vector for genetic engineering must have specific features that facilitate the cloning and manipulation of DNA.

2. **Origin of Replication (ORI)**:
- The vector must contain an **Origin of Replication (ORI)** site. This is crucial because it is the site where DNA replication begins, allowing the vector to replicate within the host cell.

3. **Restriction Sites**:
- The vector must also have **restriction sites**. These are specific sequences where restriction enzymes can cut the DNA. This feature is essential for inserting foreign DNA into the vector.

4. **Marker Sites**:
- A **marker site** is necessary for identifying successful transformations. This often includes genes that confer resistance to antibiotics. By using these markers, researchers can select for cells that have successfully taken up the vector.

5. **Conclusion**:
- Therefore, a suitable vector for genetic engineering must include all of the following: ORI, restriction sites, and marker sites. Thus, the correct answer is "all of these."

### Final Answer:
The correct option is **all of these** (ORI, Restriction site, Marker site).

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