Step 1. A target sequence of DNA within the genome is identified and a strand of guide RNA is created that binds to the target DNA sequence.

Step 2. The guide RNA binds to target DNA sequence in the genome.

Step 3. The Cas9 enzyme binds to the guide RNA.

Step 4. The Cas9 enzyme cuts both strands of DNA in the genome.

Step 5. The cut is repaired by the cell’s own repair mechanisms, introducing a genetic change (mutation).

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