Question

Which of the following nuclease is/are used in genetic engineering?

• A. ZFN
• B. EcoRI
• C. Cas9
• D. More than one answer are correct

Hint:

Restriction enzymes (like EcoRI) are "molecular scissors" for cloning, while ZFN, TALENs, and Cas9 are "molecular scalpels" used for precision genome editing.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Nucleases are enzymes that cleave the phosphodiester bonds between nucleotides in nucleic acids. In genetic engineering, nucleases are essential tools for "cutting" DNA at specific sites to allow for the insertion, deletion, or modification of genetic material.

Step 2: Detailed Explanation:
1. ZFN (Zinc Finger Nucleases): These are engineered site-specific nucleases. They consist of a DNA-binding domain (Zinc fingers) fused to a non-specific cleavage domain (FokI). They were among the first tools used for precise genome editing.
2. EcoRI: This is a classic Type II Restriction Endonuclease derived from E. coli. It recognizes and cuts a specific palindromic sequence (GAATTC). It is a fundamental tool for molecular cloning and rDNA technology.
3. Cas9 (CRISPR-associated protein 9): This is an RNA-guided endonuclease used in the revolutionary CRISPR/Cas9 system. It allows for highly efficient and programmable genome editing by cutting DNA at a site defined by a guide RNA (gRNA).
Since all three are nucleases used extensively in various stages of genetic engineering (cloning and genome editing), option 4 is the logical choice.

Step 3: Final Answer:
ZFN, EcoRI, and Cas9 are all nucleases utilized in genetic engineering. Thus, more than one answer is correct.