Transfer of bacterial genes by a phage is called:

Options

A. Transformation
B. Transduction
C. Conjugation
D. Hybridisation

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the transfer of bacterial genes specifically by a phage (a type of virus that infects bacteria).

2. **Analyzing the Options**:
- **Option A: Transformation**: This process involves bacteria taking up genetic material from their environment. It does not involve a phage. Therefore, this option is incorrect.
- **Option B: Transduction**: This is the process where a phage infects a bacterium, incorporates bacterial DNA into its own genome, and then transfers that DNA to another bacterium upon infection. This is the correct process being asked about in the question.
- **Option C: Conjugation**: This method involves direct physical contact between two bacteria for gene transfer, typically through a structure called a pilus. It does not involve a phage, making this option incorrect.
- **Option D: Hybridization**: This term refers to the fusion of different substances to create a hybrid and is not related to gene transfer in bacteria. Thus, this option is also incorrect.

3. **Conclusion**: Based on the analysis of each option, the correct answer to the question is **Transduction**.

---