CRISPR gene editing

Bacteria have been editing genes for billions of years. CRISPR—Clustered Regularly Interspaced Short Palindromic Repeats—evolved as a microbial immune system, storing fragments of viral DNA to recognize and destroy future invaders. The sequences were first observed in E. coli by Japanese researcher Yoshizumi Ishino in 1987, but their function remained mysterious for decades. By the 2000s, researchers had identified the CRISPR-associated (Cas) proteins that did the cutting, and in 2007, Philippe Horvath's team at Danisco proved CRISPR was indeed an adaptive immune system. The pieces were assembling, but no one had yet imagined using this bacterial defense mechanism as a general-purpose genetic scalpel.

The breakthrough came in 2012 when Jennifer Doudna at UC Berkeley and Emmanuelle Charpentier at Umeå University demonstrated that CRISPR-Cas9 could be programmed to cut any DNA sequence simply by changing the guide RNA. Previous gene editing tools—zinc finger nucleases and TALENs—required engineering new proteins for each target, a process taking months and costing thousands of dollars. CRISPR reduced this to designing a short RNA sequence, work that could be done in days for a few hundred dollars. The 2012 paper in Science describing 'programmable genetic scissors' opened the floodgates. Within months, labs worldwide were using CRISPR to edit genes in mice, plants, and human cells.

The adjacent possible for CRISPR was uniquely prepared. DNA sequencing had become cheap enough to study bacterial genomes systematically. RNA interference research had established that short RNAs could guide molecular machinery to specific sequences. Protein engineering from zinc finger work provided the conceptual framework for targeted DNA cutting. Perhaps most critically, the scientific infrastructure existed to rapidly disseminate and replicate the technique—the Doudna-Charpentier paper was immediately testable by any molecular biology lab with basic equipment.

Convergent emergence was dramatic. Just months after the 2012 paper, Feng Zhang at the Broad Institute and George Church at Harvard independently demonstrated CRISPR editing in human cells. The race to applications sparked a bitter patent dispute that would take years to resolve, with billions of dollars at stake. This simultaneous discovery across multiple labs confirmed that CRISPR's time had come—the adjacent possible had fully matured.

The cascade of enabled innovations was immediate and transformative. CRISPR-based therapies entered clinical trials for sickle cell disease, inherited blindness, and cancer. Agricultural applications emerged for disease-resistant crops and hornless cattle. Base editing and prime editing refined the technique for single-letter DNA changes without cutting. In 2020, Doudna and Charpentier received the Nobel Prize in Chemistry, the fastest Nobel award from discovery to prize in the chemistry field. By 2025, the first CRISPR therapy—Casgevy for sickle cell disease—had been approved by regulators in the US and UK, marking the transition from research tool to clinical reality.