The linking of antibiotic resistance gene with the plasmid vector became possible with

Options

A. DNA polymerase
B. Exonucleases
C. DNA ligase
D. Endonucleases

Answer

To solve the question regarding the linking of the antibiotic resistance gene with the plasmid vector, we need to identify the enzyme responsible for this process. Here’s a step-by-step breakdown of the solution:

### Step-by-Step Solution

1. **Understanding the Context**: The question refers to the process of genetic engineering, specifically the insertion of an antibiotic resistance gene into a plasmid vector. This is a common technique used in recombinant DNA technology.

**Hint**: Recall that plasmids are circular DNA molecules that can replicate independently and are often used as vectors in genetic engineering.

2. **Identifying the Components**: In this scenario, we have two main components:
- The **antibiotic resistance gene** (the gene of interest).
- The **plasmid vector** (which serves as the carrier for the gene).

**Hint**: Think about what a plasmid does in genetic engineering and how it can carry foreign DNA.

3. **Role of Enzymes**: To link the antibiotic resistance gene with the plasmid vector, we need an enzyme that can facilitate the joining of these two DNA segments.

**Hint**: Consider the types of enzymes involved in DNA manipulation and which ones are used to join DNA fragments.

4. **Evaluating Options**: The question provides several options for the enzyme:
- **DNA Polymerase**: This enzyme is primarily involved in DNA replication, not in joining DNA fragments.
- **Exonuclease**: This enzyme removes nucleotides from the ends of DNA, which is not relevant for joining.
- **DNA Ligase**: This enzyme is known for its ability to join two DNA fragments by forming phosphodiester bonds between them.
- **Endonuclease**: This enzyme cuts DNA at specific internal sites, which is not what we need for joining.

**Hint**: Focus on the function of each enzyme and how it relates to the process of joining DNA segments.

5. **Conclusion**: Based on the evaluation, the correct enzyme that facilitates the linking of the antibiotic resistance gene with the plasmid vector is **DNA Ligase**. This enzyme acts as a "molecular glue" to join the complementary sticky ends of the DNA segments.

**Hint**: Remember that DNA ligase is essential in creating recombinant DNA by joining fragments together.

### Final Answer
The linking of the antibiotic resistance gene with the plasmid vector became possible with **DNA Ligase**.