The understanding and application of clustered regularly interspaced short palindromic repeat (CRISPR) systems and CRISPR‐associated (Cas) nucleases have helped genome editing become a standard laboratory technique. CRISPR‐Cas nucleases are RNA‐programmed DNA‐cutting enzymes that facilitate the introduction of intentional sequence changes into the genomes of experimental cells and organisms. This overview provides a background for genome editing and CRISPR‐Cas nucleases, as well as an overview of the technology used to assess the outcomes of genome editing.