Science
What is CRISPR?
CRISPR is a gene-editing tool that lets scientists cut DNA at a precise location to disable, repair, or replace a gene. Adapted from a bacterial immune system, it is faster, cheaper, and more accurate than older methods, and is already being used to treat genetic diseases.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains crispr.
Key things to understand
- 1A guide RNA steers the Cas9 'scissors' protein to a matching DNA sequence.
- 2Cas9 cuts both strands there; the cell's repair can disable a gene or paste in a new one.
- 3It originated as bacteria's defense for slicing up invading virus DNA.
- 4Already approved to treat sickle-cell disease and being tested for cancers, blindness, and more.
- 5Editing embryos ('germline') is hugely controversial because changes pass to future generations.
Frequently asked questions
- What does CRISPR stand for?
- Clustered Regularly Interspaced Short Palindromic Repeats — the repeated DNA patterns in bacteria that inspired the tool.
- Is CRISPR safe to use in people?
- Treating body cells (not embryos) has produced real cures, but risks like off-target cuts mean it's used carefully under strict trials and oversight.
- Can CRISPR create 'designer babies'?
- Editing embryos is technically possible but banned or tightly restricted in most countries for safety and ethical reasons.