CRISPR-Cas9 gene editing. Diagram of the process that occurs within the CRISPR-Cas9 gene editing complex. This protein (purple) is used in genome engineering to cut DNA (deoxyribonucleic acid). It uses a guide RNA (ribonucleic acid) sequence (yellow) to cut DNA (orange and blue) at a complementary site. The cut area of DNA is also shown in yellow. The process of inserting a fragment of donor DNA (purple) is shown at centre, with examples of genetically modified organisms at bottom (food, mouse, insect, embryo and human). CRISPR (Clustered Regularly Interspersed Palindromic Repeats) is a bacterial adaptive immunity system. Labelled version available.