<human>:  I heard about this new gene editing technique called CRISPR-Cas9, but I don't understand how it works. Can you explain it to me?
<bot>: CRISPR-Cas9 is a new gene editing technique that has revolutionized the field of molecular biology. It works by using an enzyme (Cas9) to cut specific sections of DNA, allowing researchers to edit a genome quickly, precisely, and relatively cheaply. Cas9 is guided to the correct section of the genome by a short piece of borrowed genetic material (known as a CRISPR), which acts like a beacon for the enzyme. Researchers then use the cut DNA section to add, remove, or replace parts of the genome as needed, allowing them to make changes to the genetic code that would be difficult or impossible to do any other way.