CRISPR Technology

by The Center for Bioethics and Culture on May 2, 2018

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What is CRISPR?

CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats) is a technology that allows for the editing of genes within organisms. It is part of a wider group of technologies that allows scientists to edit genomes, but CRISPR has become the most prominently known because when used in combination with the Cas9 protein, it gives scientists a kind of precision never before seen.

Not only can it be used on animals or simpler forms of life, but it can also be used on human beings. Key here is that the precision of CRISPR allows it to make cuts in the gene that had previously been impossible by other technologies. This precision carries enormous repercussions not just for the future of medicine but also for the future of humanity as a species.

What does it do (the technical details)?

Briefly, CRISPR works by slicing out sections of DNA and replacing that removed section with a new, updated sequence of DNA. This allows the correction of mutant genes or of genetic diseases that have been handed down from one generation to the next.

For a bit more in-depth information on CRISPR/Cas9, the McGovern Institute for Brain Research at MIT has produced a helpful overview video, which is available on YouTube.

It should be added that there is much about CRISPR and Cas9 that scientists still don’t know. For example, some people’s immune systems have reacted negatively to the bacteria used in CRISPR/Cas9. Scientists have tried working around this setback by removing tissue from the patient, altering the tissue’s DNA, and then reinserting that tissue back into the patient. If large numbers of patients’ immune systems attack CRISPR as a foreign entity, it would render such treatments useless.

Why is it being developed?

US Dept of EnergyCRISPR has tremendous potential to cure a wide range of diseases linked to DNA. Early in 2017, scientists at the Lewis Katz School of Medicine at Temple University and at the University of Pittsburgh were able to successfully eliminate HIV in live mice by transplanting humanized cells into them. Further tests would be required on primates before any similar treatment could be applied to humans.

CRISPR could also provide revolutionary treatment options for cancer, which is caused by the uncontrolled mutation of cells. In 2016, German scientists stated that of the more than 500,000 mutations of cancer, 80% of these could be corrected using CRISPR/Cas9. University of Pittsburgh scientists, in 2017, were able to edit human cancer cells in mice to destroy the “command center” of the cancer cells and cause tumor growth to stop. Compared to the control group of mice with cancer that did not receive the treatment, the experimental group saw an increased survivability rate of 100%. Again, it will be a long time before this or similar treatment is applied to humans, but it carries great potential in the fight against cancer. Researchers are exploring how CRISPR might be used to correct or eliminate genetic disorders such as Down Syndrome and Huntington’s Disease, among a host of others.

CRISPR also offers revolutionary advances outside the realm of medicine, especially in the food industry. Researchers at Danisco, a company involved in food production, were the original discoverers of CRISPR. They were studying a certain bacterium, S. thermophilus, used in the production of yogurts and cheeses. It was prone to attack by certain viruses that altered the quality of the dairy products. The researchers determined that S. thermophilus produced clustered regularly interspaced short palindromic repeats (CRISPR) as a defense against the viruses. This breakthrough allowed researchers to implant CRISPR into other bacterium and improve the quality of food produced. This use of CRISPR allows food to say fresh longer and for it to be richer in vitamins and nutrients.

What issues does it raise?

In many ways, public conversation and debates about the ethics of biotechnologies like CRISPR lag well behind the realities of scientific and technological progress. It is important to encourage and continue public dialogue about the use of gene editing technology going forward. The ethical implications of using gene editing on human beings is the perhaps the greatest concern of this branch of technologies, but it is not the only concern.

Of course, the most the powerful argument given for genetic editing is the huge potential is has for curing heartbreaking and debilitating diseases. Any diseases that can be inherited, such Huntington’s diseases or inclinations towards certain forms of cancer, could potentially be eliminated thorough gene editing technologies like CRISPR. This would not only save many lives, but it would also significantly reduce the emotional and financial burdens on the families of those with these diseases. Presently, of course, such optimism is tempered by the fact there is still much we do not know about gene editing therapy. While it has the power to cure some diseases, it could lead to mutations that lead to others down the line.

Most gene editing has occurred on somatic cells rather than on germline (sperm and egg) cells. Thus, these changes are not passed down to genetic offspring. However, if genetic edits are made to embryos, or to egg or sperm cells, these changes will be inherited by all future generations. This is perhaps one of the greatest ethical concerns of gene editing of embryos, eggs, or sperm: any edits will have a ripple effect and will be passed down to generation after generation. Eventually, the entire human species could bear the marks of genetic editing.

The radical alteration of ecosystems using gene-editing technologies like CRISPR is another potential issue that cannot be overlooked. Transferring genes between species creates the potential for cross-species mutations. CRISPR might also increase the likelihood that genetic mutations will occur. There is potential for new diseases to be released, and whole species, or ecosystems, may be placed in jeopardy. The ecological effects of genetic modification could be catastrophic. Great caution is required.

CRISPR and gene editing also have the potential to save endangered species. Species could be made more resistant to environmental factors that have brought them to the brink of extinction. An infectious cancer, for instance, has ravaged the Tasmanian devil and brought the animal closer to extinction. Gene editing could remove predispositions within the devil’s DNA towards cancer. Some argue that we have a duty to protect the planet’s biodiversity. However, this raises the question of whether we have the right to alter the genetic composition of species in nature. In essence, do we have the right to “play God”? Many of the alterations we make could have unintended consequences and lead to mutations that destroy or radically change the species we originally sought to protect.

Another serious dilemma involves where to draw the line with gene editing. If editing out genetic defects to cure disease becomes commonplace, do we then allow genetic editing for aesthetic or for non-illness related reasons? Should we allow parents to have the opportunity to choose what color hair or eyes their baby will have? Or how tall or muscular he or she will be? CRISPR, as it becomes more commonplace, might allow for parents to craft their child in minute detail, truly a “designer baby.” Recall that editing of embryos would result in this genetic edits being passed down to future generations.

Aldous Huxley in his novel Brave New World foretells of future authoritarian regimes using technology similar to CRISPR to create a permanent class of underlings meant to serve the political elites. In the novel, manual laborers are edited to have inferior intelligence and to become more receptive to commands. Although the power to edit humans in such an advanced capacity has not yet been achieved, authoritarian governments have taken an interest in gene editing technology.

Chinese scientists have already conducted tests on cloned human embryos to search for a cure for fatal blood disease. These embryos were created exclusively for the purpose of being tested and then discarded. Such an approach betrays a severe callousness and disregard for human life.

It is important to remember that scientists in nations with lax bioethical standards will eventually have access to this technology. It will not remain in the hands of individuals who will be reluctant to use it. Countries with strong bioethical protections should take the lead in limiting the use of CRISPR and other gene editing technologies, and strongly enforcing international regulations against unethical use of this technology.

Oftentimes, scientific advancement is considered just a natural part of the modern age; that impersonal forces, whether we like it or not, are driving scientific and technological progress. Questions about the nature or direction of scientific research are shelved until technological advancement forces us to discuss these questions. Our thinking about science, that it is somehow set on a deterministic course, ignores the realities about the choices made by individual scientists and how resources are allotted for scientific research.

Sometimes we are locked into a mindset that if we do not allow nearly unbridled scientific advancement, then the research work of others will technologically outpace us. This sort of scientific “arms race” mentality leads inevitably to science controlling humanity rather than humanity controlling science. Some have proposed to create an international gene observatory to allow an international conversation to flourish between experts in the fields of science, ethics, and public policy in order to consider the issues raised by genetic modification. Such an international consortium would allow a conversation to take place without the pressures of national interests.

We should not focus solely or mainly on the consequences of gene editing—whether, on balance, it works out well—which is how nearly all of the current conversation around CRISPR is focused. We must also consider and discuss what it means to be human, the purposes of such things as sex and human reproduction, and how new biotechnologies such as CRISPR fit in to a robust picture of human health, human flourishing, and human thriving. This is to move well beyond a purely clinical approach that seeks mainly to determine if something can be done and that ignores or sidesteps questions regarding, for example, the intrinsic worth of having children and what it means to receive children as gifts.

CRISPR/Cas9 technologies have great potential to do good and to do harm. In some ways, it raises questions regarding the very essence of what it means to be human. The consequences of its use would be far-reaching in ways never before seen.


 
by Tim Colvin, Fordham University

 

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