WTF is CRISPR?
Forget flying cars, soon bioengineering will give us wings.
‘Derek is that you?’ you blink hazily into the mid-afternoon heat.
‘Yes mate’ Derek chirps.
‘Derek, I sent you out for dish soap and you’ve got wings’ you angrily chastise.
‘Sorry mate, they had a deal on — irresistible apparently — I simply couldn’t pass it up’ Derek annoyingly rebuts.
This might sound like the beginning to a perfectly sub-par episode of Eastenders, but for the simple fact that our Derek hasn’t just picked up a snack of 6 mega-spicy chicken wings. No, our Derek lives in the not so distant future, where bioengineering has become so prevalent that editing one’s own DNA is simple, cheap, and readily available. Our Derek has got his very own set of wings. Our Derek is a human-bird creature, and one without dish soap.
For thousands of years human beings have been engineering life. Jump in the time machine for a second. Brian, a Roman charioteer, wants to go faster in his little wooden chariot. To achieve this, he’ll need quicker horses. He knows that his friend Gregorius has a super quick stallion that gets him to market in no time. Brian likes this and introduces his fastest female horse to Gregorius’ stallion. The pair close the curtains, turn on some Marvin Gayous, take off their hooves, and some months later are the proud parents of a fast baby horse. Through selective breeding, Brian now has a quick pony that will win him races given a few years and enough hay.
So we’ve known that animals, plants, and other living things can pass down traits to their offspring for millennia, but it was not until recently that we understood this process. On the morning of February 28th, 1953, James Watson and Francis Crick discovered the magic of DNA, that it acts as the blueprint for a living thing and that this DNA recipe is passed down to offspring. Since then we have known where the set of instructions that govern our growth, development, functioning and reproduction are stored, but changing these instructions has been hard, expensive, risky, and generally out of scope.
Has been. Until we unlocked the wonders of CRISPR. CRISPR was first discovered in the 1990s and is a fundamental part of the genetic code for the immune system of bacteria. CRISPR is an acronym for its catchy longer name: Clustered Regularly Interspaced Short Palindromic Repeats. If we split that into two parts then we can understand how CRISPR works.
The second half first, Short Palindromic Repeats. These are short segments of DNA that are palindromes, i.e. the letters that make up the sequences read the same forwards and backwards. These short segments are repeated and identical, one after another, after another, but they are interspaced; they have gaps between them. Thus explains the other half of the expanded CRISPR acronym, Clustered Regularly Interspaced. So what connects the Short Palindromic Repeats? — Something called spacer DNA. Each segment of spacer DNA is unique and matches the DNA of a virus that has attacked it in the past. In short, the bacteria use CRISPR to ‘remember’ each virus that has tried to send it to an early grave.
But what’s the point in remembering your enemy if you don’t have the blastoid rifles at the ready to teach them a lesson if they come back? Enter Cas, or CRISPR-associated genes, that sit nearby CRISPR sequences and, when triggered, produce enzymes to locate and destroy invading viruses.
So, a quick recap. When a virus goes 1940s dictator vibes and invades a bacterium, the virus’ DNA is integrated into a CRISPR sequence in the bacterium’s genome. If the virus attacks again then the bacterium will remember it and deploy Cas enzymes to locate and destroy the virus.
Okay Evan you dork. You told me Derek had wings. How does that have anything to do with CRISPR and its role in the immune system of bacteria?
Well — because, as of 2012, we now know how to harness CRISPR to edit genes.
No jokes, CRISPR is science fiction, without the fiction.
Here’s how that works. Rachel has sickle cell disease which is caused by a single mutation in her DNA. In the laboratory a scientist puts on overalls and creates a strand of guide RNA that perfectly matches Rachel’s mutated DNA sequence. This guide RNA is given to CRISPR-associated protein 9 or Cas9 enzymes, which are then injected into Rachel’s bloodstream. They whizz through her body and use the guide RNA to find all of the mutated DNA sequences. Cas9 then cuts out these dodgy sickle cell inducing bits and another bioengineered vehicle inserts a healthy bit of DNA in its place. Bish, bash, bosh, Rachel is cured, and all through a magically simple and cheap procedure. An easy way to grasp this is to think of the process as the genetic equivalent of the find and replace feature in word.
This gene-editing mechanism has enormous implications for every industry. Not only will it be invaluable in curing disease, but in fighting global warming, boosting food production, granting us eternal youth, fast-tracking our evolution, designing our babies, growing wings and much more. The applications of this tool are truly as infinite as the forms of life itself. Now you might need a second to catch your breath, because I’m not Rick-rollin’ you here. No jokes, CRISPR is science fiction, without the fiction.
Anyway, it’s all well and good having this technology, but how is it being used and developed now? Will YOU ever have wings?
Since we first discovered how to use CRISPR as a gene-editing mechanism, we have been trying it out on animals. Mice have been particularly revealing when it comes to CRISPR’s therapeutic potential. The little cheese-eaters share 90% of their genetic code with us humans, and so make good test subjects. Experiments on mice have successfully used CRISPR to inhibit the formation of nefarious proteins involved with Huntington’s disease, eliminate HIV, and disable the defective gene that causes a form of muscular dystrophy. This is promising news for humans.
Gene editing is playing God and could have disastrous after effects if we are not extremely careful.
As for Derek, presuming he’s not a mouse, he might get his wings sooner if he moves to China. Human trials are prohibited in Europe and America for the time being, but are expected to be allowed starting sometime this year. China has a much simpler regulatory system when it comes to medical stuff. Some hospital committees are able to approve studies in a single day, without the need for federal approval. As a consequence, China has been carrying out the world’s first human trials using CRISPR to fight a number of cancers, HIV and HPV since 2015.
Now all of this craziness doesn’t come easily. In fact, the technology’s detractors are numerous and vocal. Gene editing is playing God and could have disastrous after effects if we are not extremely careful. We do not yet know the full consequences of changing our genes, and it is unlikely to ever be totally safe. By removing Rachel’s sickle cell disease gene, we might unintentionally cause something else to mutate in her biology. We are simply too inexperienced in this realm to have any assurances that our edits will have only intended effects.
And then say we use gene editing for germline modifications, to alter the DNA of reproductive cells, well then we have a situation where our edits become part of the human gene pool. These modifications will be inherited by future generations. The question here is whether we can ethically choose what our unborn descendants will inherit?
One thing is for certain, CRISPR has given us God’s surgical scalpel. The power that this grants us is too alluring to resist and will only grow. Future Derek might enjoy the triviality of CRISPR wings and those you might feel an ethical imperative to deny, but try to deny a dying child the elixir of life and you become a monster. CRISPR will penetrate our society by way of its therapeutic potency and then inevitably take over the rest. Why, whilst you remove little unborn Alice’s gene that predisposes her to cancer, can’t you also giver her perfect eyesight, more radiant hair, Einstein’s intelligence, and wheels for toes? You’d be a monster not to, but then maybe we’ll all be monsters soon.
This piece was featured in The Zip Files podcast — an irreverent weekly 20–25 minute podcast to help the busy millennial catch up with all of the week’s most important tech news. Here’s the episode in which this piece was featured:
On Apple Podcasts:
On Soundcloud:
