Choose the mismatched pair from given options.

Options

A. Insertional inactivation - beta-galactosidase
B. YAC vector - Yeast artificial chromosome
C. BAC vector - Largest bacteriophage vector
D. Ti plasmid - Agrobacterium tumefaciens

Answer

To solve the question of identifying the mismatched pair from the given options, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Option A: Insertional Inactivation - Beta Galactosidase**
- Insertional inactivation is a method used to screen recombinant DNA from non-recombinant DNA. It involves inserting a gene into the beta-galactosidase gene, disrupting its function. This leads to the formation of white colonies for recombinants and blue colonies for non-recombinants during blue-white screening.
- **Conclusion**: This pair is correctly matched.

2. **Option B: YAC Vector - Yeast Artificial Chromosome**
- YAC stands for Yeast Artificial Chromosome, which is indeed used for cloning large fragments of DNA, particularly eukaryotic DNA. YACs can carry large inserts that plasmids cannot accommodate.
- **Conclusion**: This pair is correctly matched.

3. **Option C: BAC Vector - Largest Bacteriophage Vector**
- BAC stands for Bacterial Artificial Chromosome, which is used to clone large DNA fragments. However, the description "largest bacteriophage vector" is incorrect. Bacteriophages are viruses that infect bacteria, and they are not the same as BACs. BACs are specifically bacterial vectors, not bacteriophage vectors.
- **Conclusion**: This pair is mismatched.

4. **Option D: Ti Plasmid - Agrobacterium Tumefaciens**
- The Ti plasmid is a well-known plasmid derived from Agrobacterium tumefaciens, which is used in plant genetic engineering. This pairing is correct.
- **Conclusion**: This pair is correctly matched.

### Final Answer:
The mismatched pair is **Option C: BAC Vector - Largest Bacteriophage Vector**.