In 2017 two very different CRISPR stories ran side by side. In San Francisco, the biohacker Josiah Zayner (who now goes by Jo) pulled out a syringe on stage and injected himself with a do-it-yourself CRISPR solution meant to switch off a muscle gene. In Japan, a team of structural biologists produced something the field had never had before: a real-time movie of the Cas9 enzyme moving along DNA, locking on to its target and cutting it.
One event showed how far the technology had escaped the laboratory. The other showed, for the first time, what the molecular machine actually looks like while it works. Together they are a good snapshot of where gene editing stood in late 2017, and the years since have answered several of the questions both stories raised.
What CRISPR is, in plain terms
CRISPR-Cas9 is a gene-editing system borrowed from bacteria, which use it to recognise and chop up the DNA of invading viruses. Scientists repurposed it into a programmable tool. A short guide RNA is written to match a chosen stretch of DNA; the Cas9 protein carries that guide, scans the genome until it finds a matching sequence next to a short signal called a PAM, then cuts both strands of the double helix.
Once the DNA is cut, the cell tries to repair it. Sloppy repair tends to disable the gene, which is useful for switching genes off. If researchers supply a template, the cell can sometimes copy in a new sequence instead. Compared with older methods, CRISPR is cheap, fast and easy to adapt, which is why it spread through biology labs within a few years of the key papers in 2012 and why Jennifer Doudna and Emmanuelle Charpentier later shared the 2020 Nobel Prize in Chemistry for developing it.
By 2017 researchers had used the method in everything from cultured human cells to mice cleared of HIV-infected cells and dogs bred with extra muscle. The excitement was huge, and headlines routinely promised that it would change the world or cure inherited disease. That enthusiasm also attracted people outside traditional science.
The biohacker who injected himself
Zayner is a biochemist who spent about two years at NASA's Ames Space Synthetic Biology Research Center in California before leaving in early 2016. He then built up The ODIN, a small company selling kits that let hobbyists try genetic engineering at home, including kits for editing bacteria and yeast.
In October 2017, during a talk on human genetic engineering at the SynBioBeta conference in San Francisco, which he also streamed live on Facebook, he injected a preparation into his forearm. According to his own account, it was designed to knock out the myostatin gene, which normally limits muscle growth. He is widely described as the first person known to inject a CRISPR treatment into himself in public. No measurable editing result was ever reported, and most scientists expected none: a single local injection of DNA is a very weak way to change enough muscle cells to make any visible difference.
The stunt worked as a provocation, though. Reporting at the time, including a New Scientist feature that put the number of interested biohackers at around a hundred, described a loose community of amateurs ready to try similar experiments. Regulators were caught off guard, because the injection was not sold as a medicine and the person taking the risk was the experimenter himself.
What happened next
Within months Zayner said publicly that he regretted the stunt, worrying that others would copy it with more dangerous products. A few did attempt self-experiments, including people who injected untested treatments in livestreams, and these alarmed doctors and ethicists. In 2019 the California Department of Consumer Affairs looked into a complaint that Zayner was practising medicine without a licence; the case was closed that September with no further action expected.
The first movie of Cas9 at work
The more lasting news of 2017 came from Japan. At a CRISPR meeting in Big Sky, Montana, that June, the University of Tokyo structural biologist Osamu Nureki showed a short, grainy clip. Sam Sternberg, then a researcher associated with Jennifer Doudna's group at Berkeley, later told The Atlantic that the audience gasped, the strongest reaction to data he had ever seen at a conference.
The work was published on 10 November 2017 in Nature Communications by Mikihiro Shibata, Hiroshi Nishimasu, Noriyuki Kodera, Seiichi Hirano, Toshio Ando, Takayuki Uchihashi and Nureki. Nishimasu shared the footage on Twitter the same day.
Single-molecule movie of DNA search and cleavage by CRISPR-Cas9. pic.twitter.com/3NQxmbvzJF
— hnisimasu (@hnisimasu) November 10, 2017
The clip is dark and blobby, but it is genuinely a film of single molecules. You can watch the Cas9 complex bind DNA, sit at its target and release the cut pieces.
How you film a single molecule
Ordinary light microscopes cannot see something as small as one protein. Before this study, Cas9's shape was known mainly from X-ray crystallography, a technique Nureki's own lab had used. Researchers coax the protein into forming crystals, fire X-rays through them at a synchrotron, and work backwards from the scattering pattern to a 3D model. The result is detailed but static, and each snapshot of a different stage can take months or years to obtain.
The Kanazawa University team instead used high-speed atomic force microscopy (HS-AFM), a method pioneered by Toshio Ando. A tiny, sharp probe taps rapidly across a surface, feeling the height of whatever lies on it, much like reading Braille. Scanned fast enough and repeated, those height maps become frames of a movie.
The video above explains the 2017 biohacking scene and the injection in more detail.
What the movies revealed
- A floppy protein that firms up. Cas9 on its own kept changing shape. Once loaded with its guide RNA it settled into a fixed, two-lobed form, confirming that the RNA stabilises the enzyme.
- Searching in three dimensions. The Cas9-RNA complex appeared to find its target by diffusing through space and repeatedly landing on DNA, rather than only sliding along it.
- Unwinding before cutting. At the target, the complex locally unwound the double helix. The nuclease region, the part that does the cutting, then fluctuated before the DNA was cleaved and the products released.
Most of this had been predicted from indirect experiments, which is why, according to the authors, some top journals turned the work down for lacking novelty. The public response was a different story. Nishimasu said the tweet drew more attention than any paper he had published, including those in Nature and Cell, and summed it up as "seeing is believing."
Myths worth clearing up
- "CRISPR lets anyone redesign their body at home." No. Editing enough cells in an adult to change a trait requires efficient delivery, careful dosing and safety testing. Home injections carry real risks of infection and immune reactions with little chance of benefit.
- "The cut is always perfectly precise." Cas9 can occasionally cut similar off-target sequences, and repairs can introduce unwanted changes. Much of the research since 2017 has gone into higher-fidelity enzymes and gentler methods such as base editing and prime editing.
- "Seeing the molecule changed how CRISPR works." The movies did not alter the tool. They confirmed models and gave researchers a way to study timing and motion that static structures cannot show.
Where gene editing stands now
The anxieties of 2017 turned out to be well placed in one area. In November 2018 the Chinese scientist He Jiankui announced the birth of twin girls whose embryos he had edited at the CCR5 gene, aiming at HIV resistance. The work was condemned worldwide, and in December 2019 a Shenzhen court sentenced him to three years in prison for illegal medical practice.
Regulated medicine moved more slowly but more convincingly. In November 2023 the UK medicines regulator approved Casgevy (exagamglogene autotemcel), the first CRISPR-based therapy, for sickle cell disease and transfusion-dependent beta thalassaemia, and US approval followed in December 2023 and January 2024. Unlike a home injection, it edits a patient's own blood stem cells in a lab before returning them, after intensive treatment in hospital.
The practical takeaway: CRISPR is now a real medical tool, but one used under strict supervision. Anyone interested in a gene therapy, or in a clinical trial for an inherited condition, should talk to a doctor rather than look for kits online.
Sources: Kanazawa University NanoLSI: Real-space and real-time dynamics of CRISPR-Cas9 (10 November 2017); Shibata et al., Nature Communications (2017); Wikipedia: Jo Zayner; New Scientist (2017); Wikipedia: He Jiankui; Wikipedia: Exagamglogene autotemcel (Casgevy); video: YouTube.
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