Genes drive organisms and slippery slopes

ABSTRACT

The bioethical debate about using gene drives to alter or eradicate wild populations has focused mostly on issues concerning short-term risk assessment and management, governance and oversight, and public and community engagement, but has not examined big-picture— ‘where is this going?’—questions in great depth. In other areas of bioethical controversy, big-picture questions often enter the public forum via slippery slope arguments. Given the incredible potential of gene drive organisms to alter the Earth’s biota, it is somewhat surprising that slippery slope arguments have not played a more prominent role in ethical and policy debates about these emerging technologies. In this article, we examine a type of slippery slope argument against using gene drives to alter or suppress wild pest populations and consider whether it has a role to play in ethical and policy debates. Although we conclude that this argument does not provide compelling reasons for banning the use of gene drives in wild pest populations, we believe that it still has value as a morally instructive cautionary narrative that can motivate scientists, ethicists, and members of the public to think more clearly about appropriate vs. inappropriate uses of gene drive technologies, the long-term and cumulative and emergent risks of using gene drives in wild populations, and steps that can be taken to manage these risks, such as protecting wilderness areas where people can enjoy life forms that have not been genetically engineered.

KEYWORDS:

• Gene drive
• CRISPR
• slippery slope argument
• ethics
• regulation

Disclosure statement

DBR, FG, JK, and RFM have no competing interests to disclose. GC does not have any financial interests directly related to this work but has filed patents on CRISPR and on RNA guided Gene Drives.

Author contributions

DBR and JK conceived of the research project. DBR, FG, JK, RFM, and GC drafted and critically revised the manuscript.

Notes

¹ Although CRISPR has received considerable attention in the scientific literature and the media, it is worth noting that other gene editing tools have been available since the 1970s and that more tools are likely to be developed in the future.[7].

² GMOs that do not incorporate gene drives have been released into the wild. Since 2009, Oxitec has conducted field trials of genetically modified (GM) Aedes aegypti mosquitoes in the Cayman Islands, Brazil, Malaysia, and the US. The current strains of Oxitec’s GM mosquitoes, have a genetic mechanism that causes female offspring to die in the larval stage unless they are exposed to tetracycline, a commonly prescribed antibiotic that does not occur in the natural environment in high concentrations. When the males are continuously released and breed with female mosquitoes in the wild, the population declines, often dramatically. Because only males with the engineered trait survive, the trait is expected to eventually be lost from the population once releases are ended.[13,14].

³ There are, however, some noteworthy cases in which GM plants have become invasive species. GM creeping bent grass, which is used as a turf for golf courses, is spreading uncontrollably across Oregon.[28].

⁴ A notable exception here are Kuzma and Rawls, who consider the development of gene drive technologies and our obligations to future generations.[36].

⁵ The other two scenarios could be topics for other papers.

⁶ Oxitec’s mosquitoes do not incorporate a gene drive system. See note 7.

⁷ This type of opposition is sometimes expressed as the view that genetic engineering is ‘playing God.’[27],[46] We will not examine that position in-depth here. It is likely that people have fundamental disagreements about the morality of GMOs than cannot be easily resolved by rational arguments or empirical evidence and that the best way forward may be to try to reach procedurally fair, political solutions that recognize the interests of different parties and allow for meaningful engagement in public decision-making.[88].

⁸ We use ‘natural’ in scare quotes here because there are significant scientific and philosophical questions about what makes something natural or unnatural [81,83,88]. Some people refer to non-GMO corn as natural, but non-GMO corn is the product of hundreds of years of selective breeding. In a sense, everything made by human beings is natural because human beings are part of nature.

⁹ We also note that non-engineered species and ecosystems could serve as a repository of valuable genes for breeding programs.

¹⁰ See note 7.

Additional information

Funding

This research was funded, in part, by the Intramural Program of the National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH). This research does not represent the views of the NIEHS, NIH, or US government..