Endonuclease is employed in

Options

A. Transcription
B. Translation
C. DNA replication
D. Genetic engineering

Answer

**Step-by-Step Text Solution:**

1. **Understanding Endonuclease**: The term "endonuclease" refers to a type of enzyme that cuts nucleic acids (DNA or RNA) at specific sites within the molecule. In the context of biotechnology, the most commonly referred endonucleases are restriction endonucleases.

2. **Definition of Restriction Endonuclease**: Restriction endonucleases are bacterial enzymes that were first discovered in the early 1960s, particularly in *E. coli*. They serve as a defense mechanism for bacteria against invading bacteriophages by cutting the viral DNA.

3. **Function of Restriction Endonucleases**: These enzymes recognize specific sequences in the DNA and cleave the double-stranded DNA at those sites. This action is often described as cutting DNA into defined fragments, which can be likened to a "chemical knife."

4. **Application in Biotechnology**: The primary application of restriction endonucleases is in genetic engineering and recombinant DNA technology. They are used to cut DNA at specific locations, allowing scientists to isolate genes of interest, insert new genes, or manipulate genetic material for various purposes.

5. **Conclusion**: Therefore, endonucleases, particularly restriction endonucleases, are employed in genetic engineering, making it the correct answer to the question.

**Final Answer**: Endonuclease is employed in genetic engineering.

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