CRISPR can rewrite our genetic code: Best ideas of the century

“The pain was like being struck by lightning and hit by a freight train at the same time,” Victoria Gray said. New scientist in 2023. “Now everything is different for me.”

Gray experienced severe episodes of sickle cell anemia, but in 2019 she was effectively cured using a revolutionary technique that allows us to make changes to specific elements of our DNA: CRISPR gene editing. In 2023, this experimental treatment became the first approved CRISPR therapy.

Hundreds of clinical trials of CRISPR-based treatments are currently underway, and this is just the beginning. CRISPR could help treat all kinds of diseases, not just genetic ones. For example, a single dose of CRISPR could reduce your risk of heart attack and stroke by permanently lowering your cholesterol levels.

And while this method isn’t yet safe enough, it seems likely that in the future CRISPR will be routinely used to edit our children’s genomes to reduce their risk of common diseases.

CRISPR is also beginning to transform agriculture by making it much easier to develop disease-resistant crops and livestock that are adapted to warmer conditions or better for food.

Considering all of this, there is no doubt that CRISPR is one of the best ideas of the 21st century. Its power lies in its ability to correct “spelling errors” in DNA. This has two parts: First, you need to place your gene-editing tool in the right place in the genome, just like moving your cursor to the right place in a long document on a computer. Then you make the change.

Microbes use this mechanism in their battle against other microbes, and before 2012, biologists had discovered many natural gene-editing proteins. However, each targeted a single location, or sequence, in the genome. To change somewhere else, the only option was to redesign the part of the protein that binds DNA to target a different sequence, a laborious process that took years.

But it turns out that bacteria have evolved a large family of gene-editing proteins that don’t bind directly to DNA. Instead, they connect to a piece of RNA – a cousin of DNA – and look for sequences that match the RNA. And producing RNA takes days, not years.

In 2012, Jennifer Doudna of the University of California, Berkeley, and her colleague Emmanuelle Charpentier of the Max Planck Institute for Infection Biology in Berlin showed how one of these gene-editing proteins, called CRISPR Cas9, could be made to target any desired sequence by adding the right form of “guide RNA.”

There are now thousands of CRISPR variants used for many purposes, but all rely on guide RNA targeting. This is world-changing technology, for which Doudna and Charpentier received a Nobel Prize in 2020.