CRISPR: Coroner tackles the ethics of gene editing

It may sound like something from a fiction movie, and just over a decade ago it probably was, but in that time, scientists have discovered a ground-breaking genetic engineering tool called CRISPR-Cas9 (often referred to as only CRISPR). 

It has the potential to revolutionize the future of human experience — from creating drought resistant crops, augmenting mosquitoes to eliminating the transmission of malaria to, most importantly, eradicating specific genetic diseases like cancer — by manipulating the blueprint of life. But could it have contradictory effects?

Coroner explores this topic in season two episode three, entitled 'CRISPR SISTR', where Dr. Jenny Cooper and Det. Donovan McAvoy investigate the death of a lab assistant who was helping in the CRISPR research that was to eradicate Lewy body dementia. Or so the scientists involved in the research implied during interrogation. 

What really happened is a bit different and we'll get to it, but let's try to answer some complicated questions first.

What in the world is CRISPR-Cas9? 

You know how you can edit anything that needs a bit of fixing, such as a video — an episode of Coroner for example — or an Instagram picture by using various apps or tools? CRISPR-Cas9 is similar, but a molecular tool, which is much more complex. 

We can only scratch the surface, but to put it in simple terms: CRISPR-Cas9 is a gene editing tool that can be used to more precisely edit targeted bits of DNA — in order to modify (strengthen, weaken, switch on and off) or eliminate specific genes in organisms like bacteria, animals, plants and even human cells. Imagine being able to prevent cancer by editing out the culprit?! Life changing!

"Think of it like editing text," says Dr. Janet Rossant, a researcher who uses CRISPR in her lab at Toronto's Hospital for Sick Children. 

"You can cursor in and you delete a few words, paste in a little sentence. And that is what people can now do in the genome."

Breaking it up, CRISPR (short for clustered regularly interspaced short palindromic repeats) is a cluster of DNA sequences found within the genomes of specific microorganisms such as bacteria. And Cas9 (CRISPR associated protein 9) is an enzyme from bacterial antiviral systems that uses those sequences as a guide to recognize, interrogate and cleave foreign DNA by unwinding it and checking for complementary sites. And then snip snip.

In his interview with The Nature of Things, Dr. Eric Olson, a Molecular Biologist at the University of Texas Southwestern Medical Center, explains it in everyday terms. 

Metaphorically speaking, he says that we can think of CRISPR as a spell checker for DNA with a two component system. One component is the molecular scissors that can cut DNA and the other a GPS device for DNA which you can program to guide and deliver the scissors anywhere in the 6 billion letters of the DNA, and cut it in two.

There are many gene editing techniques which have been around for a while but CRISPR-Cas9 is revolutionary in its precision, timeliness and cost. Researchers are working tirelessly to add more to the CRISPR toolkit, but for now Cas9 is still the most popular.

"All methods are very efficient at making site-specific mutations, but CRISPR takes the least time and has the lowest costs," said Caixia Gao, a plant biologist at the Chinese Academy of Sciences in Beijing, to sciencemag.org.

If you need more detailed explanations on CRISPR and how it works, this is where we defer to the experts and we go back to Coroner.

Coroner addresses the consequences of unethical application of CRISPR

Jenny's CRISPR case gets personal because of its ability to possibly heal her father who has the previously mentioned Lewy body dementia. Her hopes are up and after a conversation with her father, he is interested in being a part of the human trials.

Unfortunately, the scientists in the series end up on the unethical side. They've lied about experimenting with Lewy body dementia but instead were selfishly trying to cure themselves of Huntington's disease. 

To make things worse, the methods which they applied turned deadly for the assistant who initially saw them as miracle workers while they used him as a guinea pig for their personal gain and research.

As the case closes, so does the CRISPR research along with Jenny's hopes for her father's recovery. The disappointment in this episode makes for a great story... but is reality any different?

The CRISPR-Cas9 challenge

While CRISPR has the potential to save many lives, there are still many safety wrinkles that need to be ironed out before we start to see it applied in Canadian labs. As Coroner points out, CRISPR-Cas9 could unleash consequences we can't predict which could be dire.

The method relies on Cas9 to be precise but sometimes it does veer off, making off-target cuts which is where the challenges begin. It also relies on the body's natural repair system to heal the snipped area that could cause DNA mutations and other diseases.

One of the biggest controversies of CRISPR is the possibility of making permanent gene alterations which could be passed down to future generations. Creating designer babies by altering their genes to create faster and more powerful athletes or changing their hair or eye colour may sound like a no big deal to some but along with many cons, it takes away one's choice to choose their life path.

In Canada, under the Assisted Human Reproduction Act of 2004, editing the human genome is prohibited and punishable by up to ten years in prison which is why in Coroner's episode three of season two, the CRISPR lab is shut down — and the scientists arrested.

As we are propelled into the future with new bio technologies like CRISPR-Cas9, which are getting easier, cheaper and more widely accessible, the possibilities are endless and the responsibilities higher. There are many questions that still need to be answered around CRISPR like: what are the best ways of using these technologies responsibly and how can research be contained in order to avoid unethical applications?

While the scientists and the law ponder those questions, you can watch 'CRISPR SISTR' and past Coroner episodes on CBC Gem!