What Is CRISPR? A Bacterial Immune System That Became a Gene Editor

Blue cells under a microscope

In 1987 a Japanese researcher named Yoshizumi Ishino was sequencing a gene in E. coli when he found a strange pattern: a short sequence repeated five times, with unrelated stretches of DNA in between. Nobody knew what it did. It turned out to be part of a bacterial immune system, and roughly 25 years later … Read more