Technology & Medicine › Internet, genomes & AI
CRISPR gene editing
June 2012 (Doudna, Charpentier); Zhang 2013 (patent dispute)· Invention or discovery· Germs, drugs & genetics
DebatedHistorians or scientists disagree about what happened, when, or why.
A cheap, precise tool, borrowed from bacteria, for cutting and editing DNA at a chosen spot.
See it on the Technology & Medicine map →How it works
CRISPR is a bacterial defense system: bacteria store snippets of virus DNA and use them to guide an enzyme, Cas9, to cut invaders. In June 2012 Jennifer Doudna and Emmanuelle Charpentier showed Cas9 could be programmed with a short RNA 'guide' to cut any chosen DNA sequence. In January 2013 Feng Zhang's and George Church's teams used it in human cells. It is far cheaper and quicker than earlier gene-editing tools.
Why it mattered
It made gene editing routine in labs worldwide, enabling new crops and therapies, and prompted a global outcry when a Chinese scientist, He Jiankui, edited twin babies in 2018.
Think of it like
Like find-and-replace for DNA: the guide RNA finds the exact passage, and Cas9 cuts it so it can be changed.
How we know
The 2012 Science paper and Zhang's and Church's 2013 papers; the 2020 Nobel Prize in Chemistry to Doudna and Charpentier; court records of the long US patent fight.
Still unknown or debated
Who invented CRISPR editing is still contested in a US patent fight between Berkeley and the Broad Institute; Lithuania's Virginijus Šikšnys reached similar results in 2012.
Inside this (1)
Connections (4)
▸Genetic engineering (recombinant DNA) was made precise by CRISPR gene editingWell documented
The connection
Since 1973, recombinant DNA let scientists cut and paste genes, but mostly into bacteria or at random spots in larger organisms. Earlier targeted editors, zinc fingers and TALENs, needed a new custom protein for each target. CRISPR uses a short RNA guide that can be made in days, so editing almost any gene became cheap and precise.
When and how
Cohen and Boyer in California, 1973; zinc-finger editing in the 1990s–2000s; TALENs, 2010; CRISPR at Berkeley and Umeå (2012), then the Broad Institute and Harvard (2013).
How we know
Lab practice changed visibly: CRISPR papers rose from a handful in 2012 to many thousands a year, displacing older methods.
Debates and open questions
CRISPR is precise but not perfect: unwanted 'off-target' edits and large DNA deletions are still being measured and reduced.
▸Human Genome Project mapped the targets for CRISPR gene editingMostly agreed
The connection
CRISPR needs an address: a guide RNA matching about 20 letters of the target DNA. The Human Genome Project's reference sequence supplies those addresses and lets software check that a guide will not hit similar sequences elsewhere. Without a full genome map, choosing safe edit sites in human cells would be largely guesswork.
When and how
Reference genome published 2001–03 and updated since; CRISPR guide-design software from labs such as the Broad Institute from 2013.
How sure are we?
CRISPR papers and design tools routinely check guides against the human reference genome, which is how off-target risks are predicted.
Debates and open questions
The reference genome comes mostly from a few people; edits can misfire in patients whose DNA differs, which newer 'pangenome' references aim to fix.
▸CRISPR gene editing led to the First approved CRISPR therapy (Casgevy)Well documented
The connection
Casgevy uses CRISPR-Cas9 to cut one spot in patients' blood stem cells: a switch region of the BCL11A gene that normally shuts off fetal hemoglobin after birth. Disabling it lets red cells make healthy fetal hemoglobin again. It reached approval about 11 years after the 2012 CRISPR paper, fast for a new kind of medicine.
When and how
CRISPR Therapeutics, co-founded by Emmanuelle Charpentier, with Vertex; first patient Victoria Gray treated in Nashville in July 2019; approvals in late 2023.
How we know
Trial results in the New England Journal of Medicine (2021, 2024) and regulators' approval documents describe the CRISPR editing step.
Debates and open questions
Patients are being followed for 15 years to check that the edits stay safe and effective; rival gene therapies compete for the same patients.
▸CRISPR gene editing now edits pig organs for Organ transplantsWell documented
The connection
Pig organs are about the right size, but human immune systems reject them and pig DNA carries dormant viruses. CRISPR lets scientists make dozens of edits at once: removing pig sugar molecules that trigger rejection, adding human genes, and disabling the viruses. Several living patients received gene-edited pig kidneys in 2024–25.
When and how
eGenesis, a Massachusetts company, bred pigs with 69 edits; Massachusetts General Hospital transplanted one kidney into Richard Slayman in March 2024; more patients followed in 2024–25.
How we know
Published case reports and US FDA clearance of the first formal clinical trials in 2025; one patient lived about nine months with a pig kidney before its removal.
Debates and open questions
Long-term results are unknown: early recipients died or had organs removed within months, and whether hidden pig viruses pose risks is still being studied.