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Genome editing – the key ethical issues

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Written by Dr Christopher Gyngell

This article originally appeared on the OMS website

The Nuffield Council of Bioethics released a report last Friday outlining the key ethical issues raised by genome editing technologies.

Genome editing (GE) is a powerful, and extremely rapidly developing technology. It uses engineered enzymes to make precise, controlled modification to DNA. It has the potential to radically transform many industries, including medicine, agriculture and ecology.  Despite only being developed in the past few years’, GE has already been used to create malaria-fighting mosquitoes, drought resistant wheat, hornless cows and cancer killing immune cells. The potential applications of GE in a decade are difficult to imagine. It raises a wide range of ethical issues that require careful scrutiny.

The Nuffield Council of Bioethics has formed a working group to analyse these issues. Their report titled “Genome editing: an ethical review”, is the first output of this working group.  It is a mapping project which identifies the major ethical issues arising from GE.

The report identifies several areas of GE that raise pressing ethical issues.  GE for human reproduction, and GE in livestock, are classed as requiring ‘urgent’ attention. GE for the purposes of xenotransplantation, and to alter wild populations of mosquitoes (and other disease causing animals), are classed as requiring attention ‘in the near future’.

It is unsurprising that genome editing for human reproduction is listed as requiring urgent attention. It has been at the centre of public debates about GE since scientists used the technology to alter human embryos for the first time last year. To date, only two studies involving human embryos have been performed. Both studies used unviable embryos, and had mixed results. Furthermore, considerable regulatory changes would need to take place before GE for human reproduction could become widespread. The issue is considered by The Nuffield Council to require urgent attention, then, not because it is imminent, but because of the complexity of the ethical issues it raises. There is little agreement on when, and for what purposes, it would be permissible to alter an embryos gene. The report notes that the careful examination of the ethical arguments for and against altering a human embryo, and building a public consensus on such issues, will take a long time. It is therefore vital that we start the discussion now.

Genome editing in livestock presents less complex ethical issues than in human reproduction. The same ethical issues that arise with genetically modified organisms generally (food safety, environmental contamination), apply to genome edited livestock.  However, the Nuffield Council considers this as an urgent issue because the research is so far advanced. Genome altered livestock could be in our supermarkets soon.  Pigs who are resistant to African Swine fever (which normally has a mortality rate of 90%) have already been created with GE. Such work is promising for a number of reasons. Increasing disease resistance in livestock not only increases food production, but also reduces the need for antimicrobials in farming, which has been cited as a significant cause of emerging antibiotic resistance. Furthermore, increasing disease resistance in livestock could reduce the incidence of zoonotic disease in humans, such as swine flu. Many other applications of GE in livestock, aimed at increasing food production and improving animal welfare, are currently being developed.

As genome edited livestock are just around the corner, The Nuffield Council sees an urgent need to assess if the current regulations that cover genetically modified organism (GMOs) are appropriate. Furthermore, there remains strong public opposition to eating GMOs.  The success of any attempts to commercialise edited livestock will depend on the public acceptance of it. Building a public consensus on the use of GE in livestock is therefore vitally important.

Another use of genome edited animals discussed by the Nuffield Report is in xenotransplantation. Xenotransplantation is the process of transplanting organs from one species to another, for example, pig hearts into human patients. A longstanding challenge for pig to human xenotransplantation is the presence of porcine endogenous retrovirus (PERV) in pig cells. PERV can jump from pig cells to human cells, potentially causing fatal disease.  GE provides a novel solution to this problem. In a recent study, GE was used to inactivate 62 genes associated with PERV in a pig cell line. This potentially makes xenotransplantation a realistic option in the future. Xenotransplantation raises well-known ethical issues, such as animal welfare, that will need to be revisited as research progresses.

The final areas of GE identified by The Nuffield Council as raising pressing ethical issues is its use to alter wild species of animals, such as mosquitoes, to combat infectious disease. One recent study used GE to make mosquitoes which were unable to carry the parasite that causes malaria. There are established international regulatory pathways for the release of genetically modified mosquitoes, created with older genetic engineering technologies. These will need to be reviewed to determine if they are appropriate for GE mosquitoes.

In sum, The Nuffield Council’s report highlights the vast range of opportunities created by advances in GE.  GE is a truly revolutionary technology. Most laws, and regulations regarding biotechnologies were drafted in an era with very different, and much cruder, technologies. The precision of GE, combined with its ease of use and rapid development, is putting pressure on our current regulations. It is time reassess these regulations and update our ethical analysis of biotechnologies. The Nuffield Council’s report is a good first step.

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