During gene cloning, which is called 'gene taxi'?

Options

A. Vaccine
B. Plasmid
C. Bacterium
D. Protozoa

Answer

**Step-by-Step Solution:**

1. **Understanding the Term 'Gene Taxi':** The term 'gene taxi' refers to a mechanism or entity that transports genes from one location to another. In the context of gene cloning, it is essential to identify what serves this transport function.

2. **Identifying the Role of Vectors:** In gene cloning, vectors are crucial as they carry foreign DNA into a host cell. Vectors can be plasmids or bacteriophages, and they are designed to facilitate the transfer of genetic material.

3. **Defining Plasmids:** Plasmids are small, circular DNA molecules found in bacteria. They replicate independently of chromosomal DNA and can carry genes that provide advantages, such as antibiotic resistance.

4. **Features of Plasmids as Vectors:** Plasmids have several key features that make them suitable as vectors:
- **High Copy Number:** They can replicate many times within a host cell, allowing for the production of multiple copies of the inserted gene.
- **Easy Linking of Foreign DNA:** Plasmids can be engineered to include restriction sites where foreign DNA can be inserted easily.
- **Selection of Recombinants:** Plasmids often contain selectable markers (like antibiotic resistance genes) that help in distinguishing between cells that have taken up the plasmid with foreign DNA (recombinants) and those that have not.

5. **Conclusion:** Given the definition and function of plasmids in gene cloning, it is accurate to refer to plasmids as 'gene taxis' since they transport the desired gene into the host organism. Therefore, the correct answer to the question is **plasmid**.

**Final Answer:** Plasmid is called 'gene taxi' during gene cloning.

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