CRISPR Explained
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a bacterial defense system that scientists repurposed into a precise pair of molecular scissors for editing DNA.
How it works
- A guide RNA matches a target DNA sequence
- The Cas9 enzyme cuts the DNA at that spot
- The cell's repair machinery then inserts, deletes, or replaces the code
Why it's a big deal
Older gene editing was slow and expensive. CRISPR is cheap, fast, and programmable — you just change the guide RNA to target a new location. That dropped the cost of editing a gene from months of work to an afternoon.
Real-world uses
- Agriculture — disease-resistant and drought-tolerant crops
- Medicine — therapies for sickle cell disease, approved in 2023
- Research — knocking out genes to learn what they do
The ethics
Editing somatic cells (the patient's body) treats disease. Editing germline cells (eggs, sperm, embryos) changes DNA passed to future generations — a line most countries have paused at.
The tool is powerful. The decisions around it are harder than the science.