Will Canadians Benefit from the Revolutionary Gene Editing Tool CRISPR-Cas9?

Contributed by Anita Sengupta

Introduction

Recent technological developments in the field of genetics have revolutionized biomedical research in ways we could not have imagined even a decade ago. In 2003, the Human Genome Project mapped out the full sequence of the human genome. In 2011, scientists developed a gene-editing tool called Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR-Cas9) that can be used to directly manipulate plant, animal and human genes. Together, the human genome blueprint and CRISPR-Cas9 promise to revolutionize the treatment of both hereditary and other diseases, such as cancers, cystic fibrosis and AIDS. It also opens up the possibility of using organs from different species in human transplantations and removing allergens from peanuts.

Despite such great promise, ethical and social concerns over gene editing have restricted the use of CRISPR-Cas9 in Canada. Canada has some of the most restrictive gene editing laws in the world, where gene editing on inheritable genes is a criminal offense, punishable by up to 10 years in prison. In this article, I will consider what effect Canada’s strict gene editing laws have on scientific and medical progress in Canada and explore the potential beneficial and nefarious uses of the gene editing tool CRISPR-Cas9.

What is CRISPR – Cas9?

Bacteria are under constant attack from viruses and in order to protect themselves from repeat attacks from the same virus, bacteria strengthen their immune system by collecting the attacking virus’ genetic information, in the form of ribonucleic acid (RNA). The bacteria store the virus’ genetic information inside their own genome, in a cluster known as Cluster Regularly Interspaced Short Palindromic Repeats’ (CRISPR). The bacteria uses CRISPR like a rogue gallery and when it comes under attack from a virus again, it compares the incoming virus’ genetic information to that stored inside its CRISPR, and if the sequences match, the bacteria produces a special enzyme called Cas9 to destroy the attacking virus by chopping it up.

10e8cf61113455.5a63fd64b7189.png An illustration of how CRISPR-cas9 works. || (Source: Behance // Fabian Molina and Joash Berkeley)

In 2012, Jennifer Doudna from the University of California, Berkley discovered that the Cas9 enzyme could be fed artificial RNA of the scientists’ choice, and the enzyme would then search for anything with that same code and chop it up. In 2013, Feng Zhang, a scientist at the Broad Institute in Boston, built on Doudna’s discovery and demonstrated that CRISPR-Cas9 could also be used to edit the human genome.

Gene-Editing Law in Canada

In Canada, there is a ban on human embryo research, which was fuelled, in part, by the Canadian public’s negative reaction to the 1996 British cloned sheep named Dolly. In 2004, the Canadian parliament enacted the Assisted Human Reproduction Act that made editing the human genome in any way that could be inherited, even in a laboratory setting, a criminal offense, punishable by up to 10 years in prison. The Act states “No person shall knowingly […] alter the genome of a cell of a human being or in vitro embryo such that the alteration is capable of being transmitted to descendants”. The Act justifies this prohibition by asserting that it will preserve and protect “human individuality and diversity, and the integrity of the human genome.”

Dr. Janet Rossant, a senior scientist at the Hospital for Sick Children in Toronto, has been a pioneer in using CRISPR-Cas9 to manipulate mice genes and argues that this ban is too extreme. Dr. Bartha Knoppers, a lawyer and bioethicist at the Centre of Genomics and Policy at McGill University, goes further and argues that Canada’s laws violate article 27 of the United Nations’ Universal Declaration of Human Rights because it blocks people’s right to benefit from scientific discoveries. She believes that “a more responsive system that reflects not only changes in technology but also reflects changes in society” should replace the current inflexible law.

32199915928_371cad76bf_k.jpg Jennifer Doudna, University of California, Berkeley, speaks at 2nd International Summit on Human Genome Editing in Hong Kong. || (Source: Flickr // The National Academies)

There are still no international enforceable laws that prevent genetic editing of inherited genes on a worldwide scale, even though UNESCO called for a moratorium on gene editing in 2015. Countries like France, the UK and Sweden allow research on human embryonic cells. In the UK, the use of CRISPR in research on human embryos was approved in 2016. The US only prohibits public funding of gene editing work but does not altogether prevent it from happening. Canadian scientists feel that they are falling behind other countries, and many are working through an organization called the Stem Cell Network that has been calling for the federal government to change the law.

Potential Beneficial Uses of CRISPR-Cas9

While gene editing itself is not new, CRISPR-Cas9, which uses the Cas9 enzyme to search for the exact match before it cuts genes, is far more precise than any other genetic tool used in the past. In addition, CRISPR-Cas9 is fast and cost effective. To date, scientists have successfully used the CRISPR-Cas9 tool to eliminate genetic mutations that cause Huntington’s disease, cystic fibrosis and mutations linked to some breast and ovarian cancers. Since scientists are still perfecting the art of gene editing, these tests have only been carried out in laboratories. The CRISPR-Cas9 tool can also remove bacteria and viruses from cells, such as removing the HIV virus from infected cells. Scientists are also looking to use CRISPR-Cas9 to remove allergens from peanuts.

Pioneers of xenotransplantation, the transplantation of organs from a different species to a human, have been considering the use of pig organs in humans. However, until the discovery of the CRISPR-Cas9, this was not possible because the pig carries a virus known as porcine endogenous retrovirus (PERV), which is potentially harmful to humans. In 2017, scientists at Harvard Medical School successfully removed the PERV virus from the pig’s DNA using the CRISPR-Cas9 tool. The possibility of using pig organs in humans offers hope to thousands of patients waiting for organ transplants around the world.

Possible Nefarious Uses of CRISPR-Cas9

As with any great technological advancement, the CRISPR-Cas9 tool can be misused. One such example of misuse is in the creation of “designer babies”. There is concern that parents will soon be able to pick their baby’s genetic traits, potentially removing the diversity of human characteristics. These fears are not completely unfounded because in November 2018, a Chinese scientist, He Jianjul, used CRISPR-Cas9 to modify inheritable genes of twin girls to make them resistant to HIV. This news was greeted with widespread condemnation from the international scientific community, who fear that this might be the beginning of designer babies.

36473308551_fe92d9a5e2_b.jpg CRISPR-Cas9 in Neurons. || (Source: Flickr // NIH Image Galleries)

Scientists also fear that any gene editing on inheritable DNA such as early embryos, sperms and eggs would affect not only the genetic makeup of the resulting child, but also that of the child’s offspring. UNESCO’s Member States in the Universal Declaration on Bioethics and Human Rights, 2005, declared that the human genome is part of the heritage of humanity and needs to be protected. Since the use of the CRISPR-Cas9 tool is relatively new, there are concerns over the safety of gene editing procedures. Future generations are affected and cannot consent to changes made to their DNA, so this raises major ethical, political and social justice concerns.

Conclusion

It is natural for the public to have concerns about gene editing because like any other powerful technological advancement, the CRISPR-Cas9 tool can be misused. Yet, most scientists agree that with strong international ethical guidelines and stringent international laws, this risk can be minimized. CRISPR-Cas9 has opened a huge window of opportunity to improve human health. This is just the beginning, and the possibilities of positive medical and social impacts appear limitless. While it is important to guard against the prospect of “designer babies” and protect the integrity of the human genome, given the potential widespread benefit of using CRISPR- Cas9 for human genome editing, it may be time for the Canadian government to revisit its ban and consider changes to the current legislation.

Anita Sengupta is a Junior Online Editor for the McGill Journal of Law and Health. Anita is a first year BCL/JD student and currently holds the Wainwright Scholarship at McGill University’s Faculty of Law. Anita has an honours bachelor’s degree in Humanities and Biology from Carleton University, where she was awarded the University Senate Medal for outstanding academic achievement. During her undergraduate studies. Anita received an NSERC research award, which she used to conduct research in molecular biology and genetics. Anita’s research focused on the identification of the protein-protein interactions involved in the transcription of the MYB gene for the production of suberin in plants. The aim of her research was to increase the production of suberin, a protective coating in plants, to make them more resistant to drought and disease. Anita is also interested in the holistic delivery of palliative care and presented a research poster at the Global Health Conference 2018 hosted by the University of Ottawa Medical School.

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