ELI5: How does CRISPR fix genes?

CRISPR fixes genes by acting like a tiny pair of scissors that can cut out bad parts of our DNA and sometimes replace them with good ones.

Imagine your body is like a big instruction manual, and each page tells your body how to grow and work. These pages are made of DNA, and the words on the pages are genes. Sometimes, there's a typo in the manual, a misspelled word (a bad gene) that makes your body not work right, causing sickness.

CRISPR is like a super-smart word processor with a "find and replace" function for your DNA. Here's how it works:

• First, scientists design a special guide, like a little GPS, that tells the CRISPR "scissors" exactly where the typo is on the DNA page. This guide is called guide RNA.
• Then, the CRISPR "scissors" (an enzyme called Cas9) follows the GPS and cuts out the bad word (the bad gene).
• Now, there's a blank space where the typo used to be. Sometimes, your body's own repair system will try to fix the break. This might mess things up even more, which can be useful for shutting down a problem gene.
• Other times, scientists provide a "correct" word (a healthy gene) along with the CRISPR tool. The body can then use this correct word to fill in the blank space, fixing the typo!