A recombinant DNA molecule can be produced in the absence of the following :

Options

A. Restriction endonuclease
B. DNA ligase
C. DNA fragments
D. E. coli

Answer

To determine which component is not necessary for the production of a recombinant DNA molecule, we can analyze the roles of each option provided.

### Step-by-Step Solution:

1. **Understanding Recombinant DNA Technology**:
- Recombinant DNA technology involves combining DNA from different sources to create a new genetic combination. This is typically achieved through the use of specific enzymes and vectors.

2. **Identifying the Components**:
- The options given are:
- A) Restriction endonuclease
- B) DNA ligase
- C) DNA fragments
- D) E. coli

3. **Role of Each Component**:
- **Restriction Endonuclease**: These enzymes are crucial for cutting DNA at specific sequences. They create the necessary ends for DNA fragments to be joined together.
- **DNA Ligase**: This enzyme is essential for sealing the nicks in the sugar-phosphate backbone of the DNA, thus joining the DNA fragments together to form a recombinant DNA molecule.
- **DNA Fragments**: These are the pieces of DNA that are to be combined. Without these fragments, there would be nothing to recombine.
- **E. coli**: This bacterium is often used as a host for cloning and expressing recombinant DNA. However, it is not required for the actual process of creating the recombinant DNA molecule itself.

4. **Conclusion**:
- Based on the roles of these components, we can conclude that E. coli is not necessary for the production of a recombinant DNA molecule. It is primarily used for the expression of the recombinant DNA once it has been created.

### Final Answer:
The correct answer is **D) E. coli**.