With the newfound discovery of enabling the study of DNA and its genes at a molecular level in 1953, scientists took advantage of this to construct a stepping stone to propel their research into something more superior: a technology called genetic engineering. Throughout the late 1960s and the early 1970s, scientists were able to isolate two types of enzymes: DNA ligase—the enzyme that conjoins the two helical strands of DNA together—and restriction enzymes, proteins that snip precise locations along the DNA strand.  These two components acting alongside one another as molecular ‘glue’ and ‘scissors’ would soon become the foundations to develop the future of gene editing. One such example to prove this is the latest technology called CRISPR-Cas9.
What is CRISPR?
CRISPR is an acronym that stands for “Clustered Regularly Interspaced Short Palindromic Repeats”.  Co-inventors Jennifer Doudna and Emmanuelle Charpentier are considered household names linked to CRISPR due to their revelation in 2012. Like previous gene-editing techniques, CRISPR can locate target sequences adjacent to the DNA strand and cut them to accommodate new nucleotides or leave the strand as it is. Yet, the reason why it is so popular under the spotlight lies within its performances.
So how does it work?
Like all findings presented in this field, CRISPR was initially discovered in archaea (and later in bacteria) by Francisco Mojica, a Spanish scientist at the University of Alicante.  They act as the first line of defence inside a bacteria’s immune system, with repeated palindromic sequences of DNA separated by ‘spacers’. Though unlike what it may suggest, its important uses juxtapose its name by an incredulous amount. These so-called spacers are a number one destination for numerous genetic materials —specifically bacteriophages, a bacteria’s number one enemy. Much like how our human immune system works, remnants of these virus’s DNA get stored in the spacers in case of future attacks, and it is this particular reason why scientists found a way to take this further use. First, RNA molecules—called guide RNA (gRNA)—are synthesized to compliment a specific DNA sequence scientists want to change. An enzyme called Cas9 then binds itself to the gRNA, and together, makes its way towards the target genetic code. Cas9 latches on the DNA strand, unwinds its helical structure, and proceeds to cut off the unwanted region like a piece of paper. The cell, sensing this problem, repairs the break either by simply joining the strands back together (with the absence of the unwanted nucleotides) or inserting a new gene completely. 
But what makes it so different from the others?
As the days into turn into years, the CRISPR-Cas9 system continues to prove itself to be more productive and easily customizable compared with other gene-editing techniques, and this is partly due to the fact it is not compulsory to pair with separate cleaving enzymes —it has its own snipping tool already built-in. Adding more to that, it is also inexpensive and less time-consuming, which is promptly what many laboratory companies are after. (Anyone with access to a lab can use CRISPR!). But its incredible preciseness hits the “revolutionary” mark smack-dab in the centre, launching much potential research with a range from eradicating genetic diseases to enhancing genomes. Think of possibly solving antibiotic resistance by strengthening antibiotic medicine; the health advantages of producing more nutritious foods; even reaching as far as altering human genomes completely. 
Despite a few uncertainties, there is no denying that CRISPR-Cas9 could become a new norm in the distant future. With hundreds of thousands of articles surfing the internet for the past nine years and counting, it is evidence that it’s not such a complex theory to grasp. Who knows? Maybe a number of years from now, humans can spend a cheap fee to change their eye colour permanently. What about making your height a bit taller? It is all just a matter of “who knows?”.
1 An Introduction to Genetic Engineering by Desmond S. T. Nicholl
2 Questions and Answers about CRISPR
3 CRISPR: A game-changing genetic engineering technique
4 Explainer: How CRISPR works
5 A simple guide to CRISPR, one of the biggest science stories of the decade