CRISPR

CRISPR is a gene-editing tool that lets scientists cut out and replace damaged DNA

One of the most significant advances in modern medical science, CRISPR is a molecular tool for making precise changes to a gene's DNA. The technology has already been approved for treating sickle-cell disease.

Different enzymes can be used in the CRISPR system to modify how DNA is cut

The system uses RNA sequences to guide enzymes like Cas9 to specific spots in DNA, where they cut or modify genes. Unlike Cas9, the Cpf1 enzyme makes staggered cuts, which helps insert new DNA more cleanly.

CRISPR-Cas9 enables precise genome editing using a simple RNA-guided system

Jennifer Doudna's research uncovered how bacteria use the tool as an immune defense by cutting viral DNA. She and Emmanuelle Charpentier received the 2020 Nobel Prize in chemistry for showing how this mechanism could be engineered to target and edit genes in living cells.

Despite its potential, CRISPR still fails 15% of the time

Biochemists from UIC found that persistent Cas9 binding to double-strand breaks impacts DNA repair efficiency and the effectiveness of the gene editing tool. RNA polymerase collisions also dislodge Cas9, which affects the efficiency of the tool.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

The first CRISPR-approved treatment was for sickle cell anemia in 2023

Victoria Gray was the first patient to receive a CRISPR-based therapy, which eliminated her symptoms and restored her health. The therapy's initial cost of $2.2M has kept it out of reach of many patients.

While humans have been genetically modifying plants for millennia by selectively breeding organisms with certain traits, gene-editing tools like CRISPR have further enhanced plants, conferring resistance to drought, pests, and diseases.

As of February 2025, there are more than 150 clinical trials using CRISPR technology

The clinical trials are designed to determine whether experimental CRISPR-related therapies are safe and effective. The majority of trials involve treatments for blood disorders, including beta thalassemia.

Homology-directed repair is the DNA repair method used by cells

Environmental factors like X-ray exposure may break a strand of DNA, but cells can use a sister strand to patch the damage. Scientists exploit this system by introducing custom DNA templates, which cells use instead to make repairs.

CRISPR-Cas systems act as genetic memory banks for defending bacterial cells

When viruses called phages inject DNA into bacteria, some bacterial species store bits of this DNA in their own genomes. This allows them to recognize and destroy the same virus if it attacks again.