Single stranded DNA occurs as a genetic material in virus

Options

A. `T_(2)`
B. `T_(4)`
C. `phixx174`
D. Lambda.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which of the given viruses has single-stranded DNA as its genetic material. The options provided are T2, T4, Phi 174, and Lambda.

2. **Identifying the Viruses**:
- **T2 and T4**: Both of these are known to be bacteriophages that contain double-stranded DNA as their genetic material.
- **Lambda**: This is also a bacteriophage that has double-stranded DNA.
- **Phi 174**: This is a bacteriophage that is known to have single-stranded DNA as its genetic material.

3. **Researching Phi 174**:
- Phi 174 is specifically noted for having a single-stranded DNA genome.
- It infects the bacterium E. coli and was the first DNA-based genome to be sequenced, a significant achievement completed by Frederick Sanger and his team.

4. **Conclusion**: Since Phi 174 is the only virus among the options that has single-stranded DNA, it is the correct answer to the question.

### Final Answer:
The virus that has single-stranded DNA as its genetic material is **Phi 174**.

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