Which of the following feature of vector is required to identify the transformed cell?

Options

A. Selectable marker
B. Ori site
C. Rop
D. Restiction site

Answer

To solve the question "Which of the following feature of vector is required to identify the transformed cell?" we will analyze the options provided and determine which one is essential for identifying transformed cells.

### Step-by-Step Solution:

1. **Understanding the Question**:
- We need to identify which feature of a vector is necessary for detecting transformed cells. Transformed cells are those that have successfully taken up foreign DNA.

2. **Analyzing the Options**:
- **Option A: Selectable Marker**
- A selectable marker is a gene that allows for the identification of cells that have taken up the vector containing the gene of interest. It typically provides resistance to antibiotics or enables the cells to grow in specific conditions. This feature is crucial for distinguishing transformed cells from non-transformed cells.

- **Option B: ORI Site (Origin of Replication)**
- The ORI site is essential for the replication of the vector within the host cell. However, it does not help in identifying whether the cell has been transformed or not. It merely ensures that the vector can replicate.

- **Option C: ROP (Repressor of Primer) Restriction Site**
- The ROP site is involved in the regulation of plasmid replication and is not directly related to the identification of transformed cells. It is more about maintaining the plasmid's copy number.

3. **Conclusion**:
- The only feature that allows for the identification of transformed cells is the **Selectable Marker**. This is because it provides a means to select and identify cells that have successfully integrated the vector with the foreign DNA.

### Final Answer:
**The correct answer is: Selectable Marker (Option A)**.

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