CRISPR/Cas9 is a system that has just recently been discovered around the early 2000s and is taking the science world by surprise. This system is much more accurate compared to early gene editing systems, which makes it the new technique scientist are using. The way this system works is by targeting a specific genome and altering it. While you may think it sounds simple you might be surprised because quite frankly working with DNA sequences is very complex and hard. When looking further into the process there are two molecules used one being the Cas9 and the other being RNA. Now when a scientist picks out what DNA sequence they want to cut out in order to alter the genes they first need Cas9. This molecule is an enzyme that is inserted into the DNA sequence and cuts at a specific location in order to alter the DNA sequence where the scientist pick without harming the whole gene. Though in order for the enzyme to cut out the specific location it needs guide RNA to show it the right path. That means that the RNA is responsible for leading Cas9 to an exact spot in the DNA sequence and then performs the cut. Once the cut is made the cell recognizes the change in the DNA and tries to repair itself. However before the cell can repair itself the scientist uses a DNA repairing machine to introduce changes which will then become part of the gene. Once this process is complete the gene has the desirable trait the scientist picked out and now the process is done.

Sources:

https://www.yourgenome.org/facts/what-is-crispr-cas9

https://www.broadinstitute.org/what-broad/areas-focus/project-spotlight/crispr-timeline