The first r-DNA constructed by gene encoding the following character

Options

A. Frost resistance
B. Drought resistance
C. Pest resistance
D. Antibiotic resistance

Answer

To solve the question regarding the first recombinant DNA (r-DNA) constructed by gene encoding a specific character, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Recombinant DNA Technology**:
- Recombinant DNA technology involves combining DNA from different organisms to create new genetic combinations that are of value to science, medicine, agriculture, and industry.

2. **Identifying the First r-DNA Constructed**:
- The question asks for the first recombinant DNA that was constructed and what character it encoded.

3. **Options Provided**:
- The options given are:
- Frost resistant
- Drought resistant
- Pest resistant
- Antibiotic resistant

4. **Researching Historical Context**:
- The first successful construction of recombinant DNA was accomplished by Stanley Cohen in 1972.

5. **Determining the Character**:
- The character encoded by the first recombinant DNA was related to antibiotic resistance. Specifically, it involved the introduction of an antibiotic resistance gene into a plasmid derived from *Salmonella typhi*.

6. **Conclusion**:
- Therefore, the answer to the question is that the first recombinant DNA constructed encoded the character of **antibiotic resistance**.

### Final Answer:
The first recombinant DNA constructed encoded the character of **antibiotic resistance**.

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