> To accomplish that feat, the treatment is wrapped in fatty lipid molecules to protect it from degradation in the blood on its way to the liver, where the edit will be made. Inside the lipids are instructions that command the cells to produce an enzyme that edits the gene. They also carry a molecular GPS — CRISPR — which was altered to crawl along a person’s DNA until it finds the exact DNA letter that needs to be c…
How does it know how to gps around? From what I know everything down there is a chemical reaction with some minimal physical motion, but how do you program it to know where to change and what and how.
It doesn’t know anything about where it “needs” to go. One of the weirder and more unintuitive things about molecular biology is just how fast everything moves inside a cell. The CRISPR molecule diffuses from one side of the nucleus to the other in a couple seconds and probably bumps into the entirety of the genome in a matter of minutes or hours. It’s very, very crowded inside cells, proteins and DNA and metabolites are constantly bumping into each other and are tumbling around at frankly incomprehensible rates. So, nothing needs to “know” where it needs to go, it simply gets pushed and jostled around until arrives there and then the attraction between the CRISPR’s RNA and the DNA takes over