One of the most significant advances in modern medical science, CRISPR is a molecular tool that can make precise changes to a gene’s DNA.
An acronym for the scientific descriptor of “clustered regularly interspaced short palindromic repeats,” the CRISPR system was discovered in single-celled organisms, where it acts as an immune system, attacking invasive viruses.
But scientists have learned how to modify the CRISPR system for use as a powerful gene editing tool, which researchers are using in efforts to develop everything from new medical treatments to more robust crops.
What CRISPR Does
Genes are the blueprints for what makes you, you. We inherit genes from our parents, and they provide the instructions for everything from building your skeleton to making sure your body operates the way it is supposed to. All of that genetic information is contained in specialized molecules called DNA (watch simple explainer).
Sometimes, the sequence of a gene’s DNA varies from the “normal” sequence in a way that causes problems—ranging from an increased likelihood of getting certain cancers to conditions such as cystic fibrosis.
Scientists are excited about CRISPR because they can use it to target these variants and cut them out, replacing them with new DNA that will (hopefully) fix the problem.
How CRISPR Works
CRISPRs are tools that allow scientists to target and manipulate precise sections of DNA. These tools have two parts. The first part is a “guide RNA” that is designed to identify a specific DNA sequence and latch on to it. The second part is a Cas protein. If the guide RNA is the targeting mechanism, the Cas protein is the tool that springs into action once the targeted DNA has been identified.
The most widely used Cas protein in gene editing is Cas9, which is essentially a pair of molecular scissors that cut the DNA targeted by CRISPR. Cells try to repair the cut DNA but often include errors that deactivate the targeted gene, effectively turning it off.
But scientists are also able to create customized DNA “templates” for the cell to use as a blueprint when repairing the DNA that was targeted by CRISPR. In short, the template allows scientists to replace the targeted DNA sequence with a new one (watch overview).
Scientists can also use a wide variety of other Cas proteins (or even engineered versions of those proteins) to make many different types of edits to targeted genes.
How Researchers Are Using CRISPR
Practical applications for CRISPR are already available. Scientists have used CRISPR to create an FDA-approved treatment for patients with sickle cell disease. The treatment uses CRISPR to edit the genes that produce misshaped blood cells in sickle cell patients, essentially eliminating symptoms of the disease for at least a year (the treatment was only approved in 2023).
Separately, dozens of clinical trials are underway for treatments that use CRISPR to address everything from cancers to HIV.
Scientists are also using CRISPR to create new crops for food production, make existing crops more resilient, and improve farming sustainability. Some early field trials are underway—with some experts saying CRISPR-edited crops will be in widespread use within the next 15 years.
CRISPR Demystified: How Gene Editing Is Revolutionizing Healthcare
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One of the most significant advances in modern medical science, CRISPR is a molecular tool to make precise changes to a gene’s DNA. The technology has already been approved for use in treating sickle-cell disease, with many more patents and projects in the pipeline. Here's what we know about the tool.
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