These days, it doesn’t matter if you’re a hard-core science nerd or simply a casual I Fucking Love Science browser on Facebook – big news will reach you anyway, and in 2016, nothing is bigger than CRISPR, the shiny, new genetic modification tool that is already on track to reshape the world. Ever think that apples should be twice as big and extra juicy? Fancy another arm or two? Maybe you want your kids to have wings and be immune to heart disease? Well, thanks to this new invention, your daydreams might just become reality.
For a (very) quick refresher on the development of genetic engineering, we’ll start with DNA. DNA is a long string constructed from four different nucleotide molecules, ATCG, arranging themselves in sequences to provide instructions for the materials making up your body. Previous molecular tools would cut certain sequences of DNA (say, TCGATC) out of a gene to alter function, however, the length of the sequence used to direct the DNA editing tool would be small, which could lead to the accidental removal of similar sequences in places you don’t necessarily want to change. In addition to this, the construction of multiple tools too was inefficient, and laborious.
CRISPR/Cas9 has no such problems when it comes to sequence specificity, and is much more efficient, with the ability to edit a genome of a live organism with total accuracy and reliability. The finesse and efficiency granted by CRISPR allows scientists and researchers to quickly and precisely remove and insert genes with an unprecedented level of ease, thanks to its discovery in bacteria.
Going back as far as the 80s, scientists would notice that certain DNA sequences in bacteria would repeat over and over, with small unique regions in between these repeats. They dubbed the repeats CRISPR. Scientists then saw that the unique segments between CRISPR matched the DNA sequences of viruses that prey on bacteria. Bacteria would keep bits of viruses circulating around the cell to remember that viral strain and help defend against the virus next time it attacked. Here we had the first part of the CRISPR/Cas9 genome editing system.
A set of enzymes known as Cas9 (CRISPR-associated proteins) make up the second part of the defence mechanism, and work to precisely snip and slash the invading viruses. It was quickly figured out that Cas9 cuts and snips DNA, so that to manipulate the system for genetic engineering, you just need to ensure CRISPR told Cas9 where to cut and snip, and boom – there you have your custom made genome.
First used by its inventors in 2012 to enter microbes and remove sections of DNA from the plasmids of the cells (plasmids being small rings of DNA), CRISPR made heads turn in 2013 when it was used to cut out a particular piece of DNA from a human cell and replace it with another. Soon after, researchers at Harvard University and Broad Institute also reported success with the tool.
A dam had opened, and dozens of trials held over the next three years flooded scientific literature with developments in the CRISPR/Cas9 system. Chinese researchers have edited the genome of an embryo, changing the potential development of a human being. Earlier this year, another Chinese team removed a gene out of a lung cancer patient’s white blood cells before injecting the edited cells back into his bloodstream. More cancer-related trials are also planned next year in both the US and China.
The potential of CRISPR/Cas9 editing is endless, and fast approaching reality. Last year in the Journal of Reproductive Biology and Endocrinology, researchers from Hokkaido University in Japan predicted that doctors will be able to use CRISPR to alter the genes of human embryos “in the immediate future.”
This kind of precise modification ability has opened up doors that most barely thought existed. As mentioned, DNA is the molecule which codes the instructions for everything that you are and can possibly be. Your physical and mental limitations, while influenced by your environment, are ultimately decided by your genes. The reason you don’t come out of the womb as smart as Socrates or as strong as Schwarzenegger is due to limiting factors imposed by your genes, meaning you have to study and hit the gym to often only get a fraction of the brawn and brains you crave. With the kind of genome manipulation allowed by CRISPR/Cas9, these limits could become mere hurdles, sending the human condition careering into new heights.
Already there are talks at the international levels of the improvements to be made to the intellectual, athletic or even moral condition of the human being. Even if we look at the less romantic options such as improving the arability and quality of crops, or eliminating hereditary diseases and ailments brought about by mutations and other errors in the DNA, we can see a clear way to completely overhaul our world. The kind of developments previously confined to the fiction of comic books and movies is about to be made real.
Almost every week scientists across the world are uncovering new developments and avenues for future research in development. Diseases eliminated, new species created, and the entire biosphere shaped to our desires; I won’t be the first to suggest that CRISPR will redefine the word “human” in the next hundred years.
Abram Giller
Featured image courtesy of MIKI Yoshihito via Flickr. License here.
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