By Nathan Park Class of 2023
What is CRISPR
In the movie Gattaca, parents pay top money to genetically engineer their child to have any desired features such as a handsome face, tall height, intelligence, and athletic body. But did you know, in recent years, scientists have begun to create a technology called CRISPR-Cas9 that can do exactly this and possibly even more?
CRISPR is a powerful tool that can very easily change our world’s future with the various solutions that can be brought along with it. With its ability to edit genes, it can change the DNA of any living thing whether its plants, humans, or animals in ways we thought were ever possible.
CRISPR was initially discovered through a basic research project that looked into how bacteria fought against viral infections. While performing this experiment, it was discovered that “many bacteria have in their cells an adaptive immune system called CRISPR” (Doudna). This immune system helps the bacteria to detect where the virus is located and destroy it. In this system are “repeating sequences of genetic code, interrupted by “spacer” sequences – remnants of genetic code from past invaders.” (Broad Institute) This system works as a library so that when viruses return, the system is able to go through this library to detect and destroy these invaders. It was later in January 2013, that the Zhang lab issued a method on how to engineer CRISPR in a way that can allow it to edit genomes in both mouse and human cells. With CRISPR, scientists are able to identify mutations in genes and make changes to the DNA that may allow us to cure genetic diseases in the near future.
How does it work?
So how does this technology work? Firstly, scientists translate the CRISPR “spacer sequences” into short RNA sequences that, in turn, help to locate the sequences of DNA that needs to be changed. After finding this, a protein found in CRISPR, called Cas-9, binds to the DNA and cuts it, separating it from the mutation rest of the DNA and shutting the gene down. This allows researchers to examine this mutation and make precise changes to the human genome so that it can be reverted back to the normal sequence.
Think of it like this, imagine that you are writing an essay and you find a typo on that essay. The typo is a phrase that says “Mary had a big lamb.” There are many ways we could fix this error. We could either take out the word “big”, but then we lose the specifics of the phrase. We could also just add the word “little”into the phrase, but then it’s too complicated. So what we need to do is replace the word “big” with “little”. By giving Cas-9 an RNA that encodes the phrase, “Mary had a big lamb”, Cas-9 can go into the genome and try to locate this mutation. After finding it, Cas-9 would make a cut in the word, “big”, and replace it with a repair template that carries the word, “little”. The cell will repair itself into a sequence that now has the correct phrase, “Mary had a little lamb.”
The future of CRISPR
CRISPR is a powerful tool that can very easily change our world’s future with the various solutions that can be brought along with it. With its ability to edit genes, it can change the DNA of any living thing whether its plants, humans, or animals in ways we thought were ever possible.
The first possibility is that it could get rid of genetic diseases by correcting the errors in a human’s DNA that cause these diseases to be passed down. Hypertrophic cardiomyopathy is a heart disease that can be found in one of every 500 people worldwide. The disease involves painful symptoms that can also be very deadly. There are mutations found in genes that causes the heart to stiffen resulting in this disease. In 2017, an experiment was conducted by some scientists at the Oregon Health and Science University where they injected 54 human embryos with the CRISPR-CAS9 machinery, 18 hours after they were fertilized. CRISPR located and eradicated the genes that caused these certain mutations and the result: 36 of the embryos were found with not a single mutation in their gene while the other 13 were partially free of mutations meaning that they had a 50 percent chance of inheriting the disease. There were also off-target genetic mutations found in the cells of 13 embryos, this meant that “only some cells [would] adopt the changes, meaning that a fraction of people would inherit the mutation” (Futurism). This experiment showed that there is a chance that the burden of a family having to carry heritable diseases can be reduced and possibly, suppressed.
CRISPR also has the possibility of creating new, healthier food in the agricultural world. When scientists from the Cold Spring Harbor Laboratory in New York used CRISPR on tomato plants, they discovered a way to edit the genes of the plant that determined its size, shape, and amount so that there is a greater harvest. In addition to these higher-production crops, CRISPR also sparks a conversation involving the difference between GMOs (genetically modified organisms) and these genetically-edited crops. Although they may seem similar, they have a distinct difference in how they work. To create GMOs, one needs to insert a foreign DNA sequence into the crop’s genome so that it can transmit traits to the future organisms. CRISPR is much more precise than this; it locates specific parts of a genome and makes changes to them by taking out genes or moving them into another location. The process is quicker, simpler, and much more precise.
Lastly, with CRISPR scientists may be able to eliminate the most annoying, but also most dangerous pest. Mosquitoes kill more than 725,000 people per year due to the various infectious diseases that it carries, including the most dangerous, Malaria, which is responsible for claiming the lives of more than 600,000 people. Researchers have begun to find out ways to slow down the spread of these perilous diseases by eradicating the mosquitos’ way of transmission.
Scientists at the University of California, Riverside, used CRISPR to develop a new mosquito controlling certain traits that are commonly passed down from a mosquito to its offspring. They made changes to its wings, eyes, and cuticle development producing a yellow, wingless mosquito with three eyes. By making this mosquito, these scientists are beginning to disrupt “target genes in multiple locations of the mosquito’s genes” (Futurism) so that they can ensure that these genetic traits will be passed down and inherited, ultimately, reducing the spread of infectious diseases such as yellow fever and decreasing the victims of these small pesky insects.
CRISPR as been tested and experimented with for many years, but there are many questions that are yet to be answered and confirmed. There is still a lot of progress to be made until we can live to see a day with no mosquitoes, healthier foods, and no more heritable diseases.