First created rDNA in vitro consists of

Options

A. Pladmid DNA of Salmonella & Genophore of E,coil
B. Plasmid of E.coil & Antibiotic resistance gene of Salmonella
C. Plasmid of Salmonella & Antibotic resistance gene
D. Genophore of Salmonella & Plasmid of E.coil

Answer

### Step-by-Step Solution:

1. **Understanding rDNA**:
- rDNA stands for recombinant DNA, which is DNA that has been artificially created by combining DNA from two different organisms.

2. **In Vitro Creation**:
- The term "in vitro" means that the recombinant DNA was created outside of a living organism, typically in a laboratory setting.

3. **Components of rDNA**:
- The first recombinant DNA was created using plasmid DNA from Salmonella and an antibiotic resistance gene.

4. **Plasmid DNA**:
- A plasmid is a small, circular piece of DNA that is separate from chromosomal DNA and can replicate independently. It is commonly found in bacteria.

5. **Antibiotic Resistance Gene**:
- An antibiotic resistance gene is a segment of DNA that provides bacteria with the ability to survive exposure to antibiotics.

6. **Combining the Components**:
- The process of creating rDNA involves inserting the antibiotic resistance gene into the plasmid DNA of Salmonella, resulting in a new recombinant DNA molecule.

7. **Conclusion**:
- Therefore, the first created rDNA in vitro consists of the plasmid DNA of Salmonella and an antibiotic resistance gene.

### Final Answer:
The first created rDNA in vitro consists of **plasmid DNA of Salmonella and an antibiotic resistance gene**.

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