CRISPR-Cas9 Gene Editing Simulator

CRISPR-Cas9 uses a short guide RNA to steer the Cas9 nuclease to a matching DNA sequence next to a PAM motif, where it cuts both strands. This simulator visualizes that search-and-cut cycle directly on a rotating DNA helix: the Cas9-gRNA complex scans past a mix of true target loci and imperfectly-matched decoy sites, binding and cutting according to the guide's fidelity, then racing between two repair outcomes — precise Homology-Directed Repair when a donor template is supplied, or the faster but imprecise Non-Homologous End Joining when it isn't. Adjust search speed, guide fidelity and donor template availability to see how each shifts on-target editing efficiency against off-target risk.