Gene editing: a topic that has been circling around the scientific community for quite some time. The premise is simple - attempting to edit genomic sequences through modification, insertion, or deletion of DNA bases - yet the journey to develop accurate technology that enables us to do such a task has been a long and complex one. That is why the understanding of CRISPR-Cas9 systems in 2012 was so groundbreaking.

CRISPR, short for Clustered Regularly Interspaced Short Palindromic Repeats, is a gene editing tool that allows researchers to pinpoint specific sequences within a genome that they wish to manipulate. The theory behind CRISPR comes from its key dynamic duo: the Cas9 protein and a guide RNA sequence. The gRNA is used first in order to accurately locate the desired DNA sequence, utilizing complementary base pairing to ensure the proper segment is recognized. From there, the Cas9 protein attached to the gRNA is able to make use of its enzymatic properties in order to cleave the DNA.

Once the cut has been made, DNA repair mechanisms work to mend the incision through the addition of new bases, leading to mutations that could possibly disable the gene. By studying the effects of a turning off a gene, researchers are able to better understand its role.

Beyond that, there have been techniques put in place where new DNA sequences can be introduced. The new strand is incorporated in the space created by the incision, granting the researcher more control over the modification than they would have had if they had simply left it to repair mechanisms.