The CRISPR-Cas system, sometimes referred to as “CRISPR” for short, is a technology for editing DNA. It is made of a guide RNA and a Cas protein. The guide RNA leads the Cas protein to a particular DNA sequence. The most common and best-studied Cas protein is Cas9. Cas9 acts as molecular scissors, cutting the DNA at the location specified by the guide RNA. When DNA is cut, cells initiate a repair process that can change or edit the DNA sequence. CRISPR can remove, add, or change DNA "letters."

For more information, see our page that explains how CRISPR works, and watch IGI founder Jennifer Doudna walk through the basics of CRISPR genome editing.

Many scientists – hundreds more than the few described here – contributed to the discovery of CRISPR and its transformation into a genome-editing tool. In 1987, scientists noticed stretches of DNA with repeating sequences in bacteria. These were later named 'clustered regularly interspaced short palindromic repeats,' or 'CRISPR' for short. In the early 2000s, researchers realized that the pieces of DNA between the repeating sequences matched DNA from viruses. This insight led to experimental work published in 2007, which showed that CRISPR is an immune system that bacteria and other microorganisms use to defend themselves against viruses.

In 2012, a team including Jennifer Doudna, founder of the IGI, figured out the basic rules of Cas9 function and how to program it to make targeted DNA cuts. This team and others saw the potential to co-opt this system as a genome-editing technology, a vision quickly put into practice in early 2013. Since then, CRISPR technology has been used in labs all around the world to edit the DNA of all kinds of cells and organisms; CRISPR-based therapies have successfully been used in clinical trials; and crop plants edited with CRISPR have entered the market. In 2020, Jennifer Doudna and Emmanuelle Charpentier were honored with the Nobel Prize in Chemistry for co-developing CRISPR gene-editing technology. 

For a lively, in-depth history, listen to this episode of WNYC’s Radiolab. Hosts Jad Abumrad and Robert Krulwich talked with Jennifer Doudna, Eugene V. Koonin, Beth Shapiro, and Carl Zimmer, exploring the world of CRISPR and how it was discovered.

The CRISPR-Cas9 system works by cutting DNA at a specific location. A cell uses repair mechanisms to fix the cut. Scientists can take advantage of repair mechanisms to make edits to DNA. But this doesn’t always work perfectly. Scientists usually look for the following mistakes:

• Off-target effects: the Cas protein cuts the DNA in the wrong place. Off-target effects may be harmless, but have the potential to impair cell function, or even kill cells depending on where they occur.
• On-target rearrangements: the Cas protein cuts at the right place, but the wrong edit is made during DNA repair. This could change gene function in a harmful way.
• Immunogenicity: putting a CRISPR-based tool or therapy into an organism could provoke a dangerous immune response.

There are many things we don’t know yet about CRISPR, and there could be other risks. Like most new biotechnologies, it will take time and research to fully understand what CRISPR can do, and what the risks and limits are. This is why moving CRISPR out of research labs and into real-world applications needs to be done with thoughtful regulation.  

In the US, the FDA oversees the process of moving potential CRISPR-based therapies from the research lab to use in human patients, and the USDA, EPA, and FDA work to oversee agricultural uses. These agencies are responsible for ensuring that products that come to the mass market are safe.

To deliver CRISPR genome-editing tools to plants and animals, researchers need to get past cell barriers like the cell membrane and the plant cell wall. Researchers do this using two main methods:

1. Electrical and chemical stimulation can poke holes in cellular barriers. CRISPR tools can be delivered through these holes.
2. Researchers can make viruses that carry DNA encoding the instructions for CRISPR tools. When these viruses infect cells, they deliver the CRISPR-Cas9 DNA.

As you might imagine, the first method generally won't work as a medical treatment. In humans, this approach only works when scientists can remove relevant cells from a patient, deliver CRISPR tools in the lab, and then return the edited cells to the patient. The second method, using a virus to deliver CRISPR machinery, has a lot of potential as a clinical delivery method. However, it can be expensive and there are some technical limitations.

Researchers are actively working on improving these methods and refining these methods and further develop novel methods like lipid-nanoparticle (LNP) delivery and ribonucleic protein (RNP) delivery. 

At IGI, creating new methods for delivery and improving on existing methods is a key focus. Learn more about the IGI Delivery Collective, which focuses on delivery methods for therapeutics, and the Plant Genomics & Transformation Facility, which focuses on delivery methods for crop plants. 

News headlines report that CRISPR makes genome editing “easy,” but what does that really mean? Genome editing of any kind is a complex molecular biology procedure that requires scientific expertise and resources, including equipment and reagents. CRISPR does make it quicker, cheaper, and easier for scientists to edit genomes, but this really only applies to molecular biologists in research labs.

We know it’s exciting, but please don’t try to use CRISPR on yourself! If you want to get involved, find science outreach events in your area. These are often based out of colleges and universities, and local science museums. 

And if you really want to try some experimental work, your local community college or university extension classes are a great place to start. If you're younger, some high schools have advanced biotechnology classes and labs that may support basic genome-editing experiments. Community labs are another fantastic resource for people looking to learn and experiment safely with molecular biology.

You can keep up with IGI’s CRISPR research on our news page, by following us on Twitter, Facebook, LinkedIn, Instagram, or Youtube, and by signing up for our newsletter at the bottom of this page!

Science news sites such as Science News Daily, Chemical & Engineering News, MIT Tech Review, STAT, WIRED, and Science News for Students often cover developments in CRISPR research too.

The IGI does not support the use of genome-editing technology in human embryos or reproductive cells with the intention to establish a pregnancy or birth at this time. The societal implications of altering the human genome in a manner that will be carried into future generations are not understood and there are significant potential risks.

Our efforts to create disease therapies focus solely on making changes to cells to treat individual patients, without passing changes on to future generations.

CRISPR is a tool for editing DNA. Like other tools, it is not inherently good or bad. The outcomes depend on how we use it.

The potential benefits of using CRISPR in humans are preventing, treating, and curing diseases. Some people want to use CRISPR to “enhance” humans, but most scientists and ethicists are opposed to this.

Using CRISPR in humans brings up many ethical questions, for instance: Should humans have the right to change our own DNA? Will people getting genome-editing treatments fully understand the risks and benefits? Would treating disease and/or preventing disability lead to a loss of diverse voices and perspectives, or increase discrimination against sick and/or disabled people? Who will have access to CRISPR treatments and technologies?

At the IGI, we are committed to exploring these questions thoughtfully, communicating with the public, and developing CRISPR technologies that serve the common good. If you’re local, feel free to attend a meeting of our ethics group, which collaborates across disciplines to integrate ethics, regulation, and policy with science.

CRISPR or other genome-editing technologies could potentially be used in creating bioterror weapons. There are no known cases of people using genome editing for bioterrorism. Frankly, there are easier ways for would-be terrorists to do harm.

Creating biological weapons would require scientific expertise in molecular biology and chemistry, and resources like expensive equipment. Even for expert scientists, it would be technically challenging to engineer or disperse biological weapons of this nature. In other words, CRISPR makes molecular biology research a bit easier in general and could be used in a harmful way, but it doesn’t make it easy to create biological weapons.

There are security agencies around the world that work to prevent bioterrorism attacks. We also encourage scientists to be mindful of biosecurity implications of their research and think proactively about potential misuses. Open discussions on these topics are crucial to conducting science in an ethical way.

What CRISPR means for the future of humanity will depend on how we use it. CRISPR-based technologies could treat and even cure many diseases, help farmers grow enough to feed the expanding global population, and help combat climate change. If scientists and non-scientists work together, we can make a better world for future generations.

We've partnered with Lawrence Hall of Science and Lab-Aids to create a classroom kit. Learn more and find links to purchasing it for your classroom here. 

You can also read our how-to on making a guide RNA to knock out a gene with Cas9 and visit our “Tools & Reagents” section to find other useful protocols, plasmids, cell lines, and more. Always be sure to follow safety and ethics guidelines in your field or workplace.

Genome engineering will have a major impact on humanity’s future, so it’s important to talk about it now. We want everyone to understand the science, the enormous potential, and the ethical implications of genome editing.

If you have a genetic disease, think about whether you’d want to be part of a clinical trial one day. Look into getting your DNA sequenced, share with other patients, and connect with researchers and patient advocates through organizations like MyGene2 or the Rare Genomics Institute.

If you are a student, teacher, or just someone with an interest in science or ethics, we invite you to learn about genome engineering and to educate others. Consider writing a blog post or an article for your student newspaper. Share interesting articles on social media. Explain genome editing to your friends and family and discuss how you feel about it. Organize a public discussion in your community. Tell us how you’re getting involved and share your ideas with us on Twitter or Facebook!

If you’re local, subscribe to our newsletter by scrolling to the bottom of this page, and visit our events page to find out about upcoming events. We teach classes on CRISPR, host regular ethics discussions, and more.

We’ve created and compiled lots of resources for students and educators, most of which are available on our Education page. CRISPR Made Simple is our primer for younger audiences or anyone starting from scratch and CRISPRpedia is our textbook-style resource for more advanced learners. Lab protocols and reagents are available here. We curate high-quality CRISPR-related content in our searchable Multimedia Library. Students may particularly enjoy our “edutainment” offerings — our Phage Invaders game, our CRISPR-3D app, and our CRISPR-VR experience.

Media inquiries can be sent to Andy Murdock at igi-press@berkeley.edu. If you are a student, the answers to your questions may be found within our educational resource collection. There are written and visual pieces on genome-editing science and bioethics, explanatory videos, and many interviews with IGI founder Jennifer Doudna and other IGI members.

The potential to help people with genetic diseases motivates us to do the work that we do. Unfortunately, the IGI cannot provide personalized advice or information about specific diseases or conditions, or connect individuals with clinical trials.

You can find information on how therapies get developed, the clinical trial process, how to find clinical trials, and resources for high quality information on genetic diseases, on our Patients & Families page.

Every researcher has their own unique experience, but most scientists pursue research because they enjoy figuring out how the natural world works.

Most career research scientists earn undergraduate (B.A. or B.S.) and graduate (Ph.D.) degrees. From there, they may go on to work at non-profit research institutes, universities, biotechnology companies, pharmaceutical companies, government research agencies like the NIH, or other groups. If researchers wish to start their own labs, they complete another ~5 years of postdoctoral research and training after completing their Ph.D. It’s a long road, but one that is rich with learning and discovery. Check out our Meet an IGI Scientist series to hear about different people's paths to science. 

Many scientists do research for awhile and then switch to other scientific careers that greatly benefit from research experience but don't involve performing research. These roles range widely, but may include work in policy, communication, art, administration, journalism, or law.