You may have heard of CRISPR. It is a relatively new technology that many are extremely enthusiastic about, but what is it? Can it really have the impact that it has been promised to have? Will it truly revolutionize everything from the food industry to the clothing industry?
An Overview of CRISPR
CRISPR stands for clustered regularly interspaced short palindromic repeats. A mouthful, I know. Basically, it is a technology that allows scientists to edit the genomes of essentially any plant. The genome is the DNA of the plant. This controls everything about the plant, from what color its leaves are to how much fruit it will produce. A scientist, armed with the mapped genome of the plant, can edit certain genes (a small sequence of DNA) and see what impact it has on the plant. In this way, we can easily determine what genes control what aspect of a plant and go about finding ways to increase the expression (prevalence) of the genes we want while decreasing the expression of those we do not.
How Does CRISPR Work?
Well, most of the science is extremely complex, but here’s the gist: DNA and RNA (two nucleic acids) are made up of small bases called nucleotides. These nucleotides are the typical A, T, C, G (and U in RNA!) ones you probably learned about in biology. A bonds to T and C bonds to G. As a result of this, it is possible for a complementary strand to exist. For example, say you had a DNA strand that looked like this:
A C G T
Your complementary strand would look like this:
T G C A
These two strands would bind together.
CRISPR works using this principle. The most popular complex (think: model) of CRISPR is CRISPR-Cas9. The RNA in this form of CRISPR does two things: it recognizes a specific sequence of nucleotides in the genome (usually a specific gene), and also keeps the Cas9 proteins from floating away. The Cas9 protein’s function is to unzip the double helix structure of the DNA so that the RNA sequence can bind to its target. Once that happens, the Cas9 cuts both strands of the unzipped DNA.
Keeping up? This is pretty hard science!
Once the DNA is cut, CRISPR then inserts a different sequence of DNA. This is where the excitement lies. Scientists can essentially cut and paste any genetic sequence they want, as simply as hitting “control + C” then “control + V” on your computer. While this may seem like science-fiction-esque technology, it is already being utilized to improve agriculture.
Applications of CRISPR
Sick of apples turning brown when you cut them and leave them on your counter? CRISPR is on top of that, with no adverse effects or changes in nutritional value! On a more practical note, CRISPR is also being used to increase yields and resistances of hugely important crops like rice, which are vital in impoverished areas like sub-Saharan Africa. It is also stopping plants like the cacao tree (where we get chocolate from!) from going extinct due to viruses. It is being used for the same purposes in citrus fruit trees and banana herbs.