One amongst the following is not the property of an ideal plasmid vector :
A. It must contain ori site
B. It must have at least one selectable markers
C. It must have only one recognition site for at least one restriction endonuclease
D. The restriction site must be randomly placed in the entire plasmid

Options

A. A. It must contain ori site
B. B. It must have at least Evo selectable markers
C. C. It must have only one recognition site for at least one restriction endonuclease
D. D. The restriction site must be randomly placed in the entire plasmid

Answer

To determine which option is not a property of an ideal plasmid vector, we will analyze each option based on our understanding of plasmid vectors.

### Step-by-Step Solution:

1. **Understanding Plasmid Vectors**:
- A plasmid is an extra-chromosomal DNA molecule that can replicate independently of chromosomal DNA. It is commonly found in bacteria and is used in genetic engineering as a vector to transfer genes.

2. **Analyzing Option A**:
- **"It must contain ori site"**:
- The origin of replication (ori) is essential for the plasmid to replicate within a host cell. Therefore, this is a property of an ideal plasmid vector.
- **Conclusion**: Option A is a property of an ideal plasmid vector.

3. **Analyzing Option B**:
- **"It must have at least one selectable marker"**:
- Selectable markers (e.g., antibiotic resistance genes) are crucial for identifying successfully transformed cells. This property allows researchers to select for cells that have taken up the plasmid.
- **Conclusion**: Option B is a property of an ideal plasmid vector.

4. **Analyzing Option C**:
- **"It must have only one recognition site for at least one restriction endonuclease"**:
- An ideal plasmid vector should have at least one unique recognition site for a restriction enzyme to facilitate cloning. However, it can have multiple recognition sites as well.
- **Conclusion**: Option C is a property of an ideal plasmid vector.

5. **Analyzing Option D**:
- **"The restriction site must be randomly placed in the entire plasmid"**:
- This statement is incorrect. The restriction sites should not be randomly placed; they should be strategically located to allow for effective cloning and manipulation of the plasmid.
- **Conclusion**: Option D is NOT a property of an ideal plasmid vector.

### Final Answer:
The option that is not a property of an ideal plasmid vector is **D. The restriction site must be randomly placed in the entire plasmid**.

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