Selectable markers in PBR322

Options

A. `"amp"^(R) & "tet"^(R)`
B. ori & rop
C. Bam HI & Clal
D. PstI & PvuI

Answer

### Step-by-Step Solution:

1. **Understanding PBR322**:
- PBR322 is a plasmid vector used in biotechnology for cloning purposes. It is an extra-chromosomal circular DNA molecule found in bacteria, specifically designed to transfer foreign DNA into a host organism.

2. **Role of Selectable Markers**:
- Selectable markers are genes that confer resistance to antibiotics. They help in identifying and selecting the host cells that have successfully incorporated the plasmid containing foreign DNA.

3. **Identifying Selectable Markers in PBR322**:
- PBR322 contains two primary selectable markers:
- **Ampicillin Resistance Gene (bla)**: This gene allows E. coli to survive in the presence of ampicillin, an antibiotic that would normally kill it.
- **Tetracycline Resistance Gene (tet)**: This gene enables E. coli to survive in the presence of tetracycline, another antibiotic.

4. **Testing for Transformation**:
- To determine whether E. coli has been transformed with the PBR322 plasmid, the bacteria are exposed to ampicillin and tetracycline.
- If the bacteria survive, it indicates that the plasmid has been successfully incorporated into the bacterial DNA, as the resistance genes are expressed.

5. **Conclusion**:
- The selectable markers in PBR322 are the genes for ampicillin resistance and tetracycline resistance. These markers are crucial for selecting transformed cells from non-transformed cells.