Conjugation was first discovered in

Options

A. Salmonella
B. Streptococus
C. Bacillus subtillin
D. E.coli

Answer

**Step-by-Step Solution:**

1. **Understanding Conjugation**: Conjugation is a process by which genetic material is transferred from one bacterial cell to another through direct contact. This process is crucial for genetic diversity among bacteria.

2. **Identifying the Structures Involved**: The structures involved in conjugation are called pili (singular: pilus). These are elongated, hollow appendages made of a protein called pilin. They act as a bridge between two bacterial cells.

3. **Recognizing the Bacteria**: Conjugation has been studied in various bacteria, including E. coli, Salmonella, and others. However, the question specifically asks about the discovery of the process.

4. **Historical Context**: The first demonstration of conjugation was conducted by researchers who studied the genetic exchange in bacteria.

5. **Identifying the Researchers**: The process of conjugation was first demonstrated by scientists Joshua Lederberg and Edward Tatum in the strain of E. coli.

6. **Conclusion**: Based on the historical discovery and the options provided, the correct answer to the question is E. coli.

**Final Answer**: Conjugation was first discovered in E. coli.

---