Which of the following is not a characteristic feature of the vector pBR322?

Options

A. It has two antibiotic - resistance genes : `amp^R and tet^R`.
B. It was the first artificial cloning vector constructed in 1997 by Boliver and Rodriguez.
C. The ampicillin-resistance gene has restriction sites for Bam HI and Sal I
D. The restriction site for Pvu II is present in the replication of plasmid (rop) gene .

Answer

To solve the question regarding the characteristics of the vector pBR322, we will analyze the provided statements one by one to determine which one is not a characteristic feature of pBR322.

### Step-by-Step Solution:

1. **Understanding pBR322**:
- pBR322 is a well-known plasmid vector used in molecular biology for cloning. The name stands for "plasmid Bolivar and Rodriguez 322," named after its creators.

2. **Analyzing the Options**:
- **Option 1**: States that pBR322 has two antibiotic resistance genes (ampicillin and tetracycline).
- **Verification**: This is true. pBR322 contains genes that confer resistance to both ampicillin and tetracycline, which are used as selectable markers.

- **Option 2**: Claims that pBR322 is the first artificial cloning vector.
- **Verification**: This is also true. pBR322 was one of the first plasmids constructed for cloning purposes, developed in the 1970s.

- **Option 3**: States that the ampicillin-resistant gene has sites for BMH1 and Sal1.
- **Verification**: This statement is false. The ampicillin-resistant gene actually has restriction sites for PU1 and PST1, while BMH1 and Sal1 sites are associated with the tetracycline resistance gene. Therefore, this option is not a characteristic feature of pBR322.

- **Option 4**: Mentions that the restriction site for PVU2 is present in the replication of the plasmid gene.
- **Verification**: This is true. The PVU2 restriction site is located in the replication origin (ROP) of the plasmid.

3. **Conclusion**:
- Based on the analysis, the only statement that is not true regarding pBR322 is **Option 3**, which incorrectly associates the ampicillin-resistant gene with the restriction sites for BMH1 and Sal1.

### Final Answer:
**Option 3** is not a characteristic feature of the vector pBR322.

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