Name the useful selectable markers for E.coli ?

Answer

To answer the question regarding the useful selectable markers for E. coli, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Selectable Markers**:
- Selectable markers are genes that are introduced into cells (like bacteria) to facilitate the selection of transformed cells (recombinant cells).

2. **Function of Selectable Markers**:
- These markers typically confer resistance to specific antibiotics, allowing only the transformed cells that have taken up the recombinant DNA to survive in the presence of the antibiotic.

3. **Process of Selection**:
- After introducing the recombinant DNA into E. coli, the cells are cultured. Not all cells will take up the DNA; only the transformed ones will survive when exposed to an antibiotic.

4. **Identify Common Selectable Markers in E. coli**:
- In the case of E. coli, the common selectable markers are:
- **Ampicillin**: A beta-lactam antibiotic that inhibits cell wall synthesis.
- **Tetracycline**: An antibiotic that inhibits protein synthesis.

5. **Final Answer**:
- The useful selectable markers for E. coli are **ampicillin** and **tetracycline**.