Which statement best describes the purpose of using a high-fidelity Cas enzyme in CRISPR experiments?

• A. To reduce off-target editing
• B. To increase off-target editing
• C. To degrade RNA
• D. To plot genomic maps

Answer: (A)

In CRISPR editing, precision matters. High-fidelity Cas enzymes are designed to make the system more selective, cutting DNA predominantly at the intended target. They achieve this by requiring a near-perfect match between the guide RNA and the DNA sequence; the enzyme is engineered so that mismatches between the guide and non-target sites reduce or prevent cleavage. This strengthens editing accuracy and minimizes unintended mutations at off-target sites, which is especially important for therapeutic applications. The on-target site still matches well enough to be efficiently cut, so the desired edit can proceed. Degrading RNA or mapping genomes aren’t the roles of these high-fidelity variants—the former relates to RNA-targeting nucleases, and the latter is an analysis task that comes after editing.