CRISPR Resources

Humans have always sought to understand, treat, and prevent disease and illness. The invention of the microscope, the discovery of DNA, the mapping of the human genome, and countless other advancements in between, all mark milestones in understanding human health at the most fundamental level. Over the past two decades, a number of paradigm-shifting technologies have unlocked a once-unimaginable capability: fixing our own DNA. 

Gene editing has the potential to address the root cause of thousands of difficult diseases, from cancer to muscular dystrophy to inherited blindness. While there are a number of different ways to edit genes, the most popular method is called CRISPR. Researchers and physicians are still figuring out the best ways to put it to use in people, but have already seen some tantalizing successes. A clinical trial for a CRISPR-based therapy, for instance, has improved nearly all the symptoms of the sickle cell disease blood disorder for at least one participant. 

CRISPR (pronounced “crisper”) allows researchers to edit the material that’s passed from parent to child (DNA) inside a living cell. DNA is made up of tiny, chemical subunits called nucleotides that, when strung together, hold the information. Some of those nucleotides are part of groups, called genes, that tell a cell how to make things it needs to function. The DNA in a living thing is called its genome.

The approach relies on CRISPR-associated proteins (Cas), which scan and recognize patterns or sequences of nucleotides in the genome. If scientists want to edit a cell’s genome, they introduce a Cas protein—the most common of which, Cas9, was originally discovered in bacteria and is now made in labs—and a short chain of genetic information called a guide RNA that works a bit like a mugshot into that cell. Then, the Cas combs through the cell’s DNA until it recognizes the sequence that matches the guide RNA and then deletes, replaces, or changes some components of the sequence. 

Researchers have known for years that changes in the DNA—both one-nucleotide changes and bigger changes, such as ones that delete a whole chunk of DNA—can cause problems. For instance, cystic fibrosis, a disease that affects the lungs, is caused by alterations in just one gene. CRISPR allows scientists to correct these types of mistakes, but editing the genome doesn’t come without complications. Both hitting the right spot in the genome and getting the CRISPR components into the right cells can be tricky. Plus, CRISPR raises ethical questions about whether, when, and how it’s appropriate to change someone’s DNA.