Future Generations and Gene Drives: the Importance of Intergenerational Equity

The Problem

A few years ago, I was preparing a slide presentation at home with my oldest daughter sitting next to me. As an artist, writer, and musician, she has little interest in what I do for a living. Yet that day she looked over my shoulder, saw my title slide, and asked, “What is synthetic biology?” After my initial shock that it should interest her at all, I tried to explain synthetic biology to her in the most neutral and balanced way possible. I said something about how synthetic biology involved the design and construction of new biological parts and systems, (sometimes living systems), or the re-design of existing living or non-living biological systems for useful purposes, such as energy, clean water, food, or chemical production. She replied “Yuck, why would anyone want to do that?”

Her immediate and strong reaction surprised me. After all, her generation lives on hi-tech and social media, and she inhabits a highly managed suburban ecosystem. The artificial world is “natural” to her. Exposure to “untouched” nature has been limited to occasional excursions to National Parks and even rarer camping trips. Our family is not outdoorsy or all-organic, and many a genetically-engineered food can be found in our household at any given time. Why then did she intuitively reject synthetic biology and the human desire to alter living organisms? Do most kids feel this way? Do children have an innate sense that the “natural” world, untouched by human interference, has the greatest value? I searched for national polls or discussions with youth about emerging applications of genetic engineering and could find none. Although my daughter’s generation will inherit the consequences of today’s deployment of new genetic engineering technologies, no one seems to be asking them what they desire of their future world.

The Technology

Today’s genetic engineering methods are allowing scientists to insert genes into organisms that have the potential to spread themselves throughout natural populations. These are called gene drive systems. Gene drive systems are based on gene editing proteins and cellular repair machinery. They can be designed to cut an essential target gene in the organism and deactivate it, so that the population dies off, or they can be used to carry extra “cargo” genes into populations to confer desirable traits.

To date, most genetically engineered organisms (GEOs) released into natural or agricultural environments are not expected to spread over time because they are usually less fit than native populations. Also, regulatory systems have stressed the need for plans to contain GEOs to certain areas like field trials, food production systems, or geographic regions that have given approval for their release. Yet GEOs with gene drive systems are designed to do the opposite, to spread and mate with wild relatives in order to drive their genes into the native population.

Specific purposes of gene drives are limited only by the traits that can be inactivated, replaced, or introduced. Proposed applications for deploying gene drives into the environment include: eradicating insect populations that carry human disease; enhancing agricultural safety and sustainability; protecting threatened species, and controlling invasive species.

So far, governance of gene drive systems has focused on questions of ecological risk and benefit. For example, for gene drives designed to eliminate pest populations, how would the disappearance of a species affect ecosystem functioning or services? Could other more harmful species fill the ecological niches of the eradicated organisms, perhaps ones spreading even more detrimental human, agricultural, or ecological disease? What is the potential for horizontal gene transfer of the gene drive system into other species like predators, and would the impacts be harmful to these populations? Although ecological risk assessment should be a key part of decisions whether to release a gene drive (and indeed most regulatory policies are based on risk-benefit estimations), there has been a push for a broader framing of issues that should be considered in decision making about gene drives. The eradication of wild pigs in Hawaii using population suppression (by conventional techniques, not gene drives) illustrates the importance of broader assessments. Feral pig eradication is desirable to reduce ecological damage to indigenous species, but Native Hawaiian communities and others who rely on the pigs for cultural events and food are opposed to it. Values of ecosystem protection and cultural preservation appear in conflict. In some cases, hunters have formed alliances with Native Hawaiian cultural groups against such efforts, and the controversy over pig eradication continues today.

Intergenerational Equity

Although discussion of some of the societal issues for gene drives has begun in the scientific literature, the media, and among key scientific and policy organizations, consideration of the potential consequences of gene drives for future generations has been virtually absent.[1] Work on intergenerational justice and obligations is not well developed in the field of ethics. Some proposed principles of intergenerational equity (IE) would require that the well-being and desires of future generations be taken into account when making decisions. This is based on the premise that all generations are partners in ensuring human survivability and well-being. Because the goals and objectives of society extend beyond the current generation and cannot often be achieved in the present, each generation is morally obligated to support human continuity by protecting resources essential for life to ensure the dignity and well-being of Earth’s current and future inhabitants. Present generations are indebted to past ones for the resources that ensure their well-being and hold these resources in trust for the next generation.

Although intergenerational equity has been a prominent concern in international policy making in areas of climate change and sustainability, it is seldom discussed in the context of genetic engineering of species destined for environmental deployment.[2] Questions associated with IE include: (1) How would the deployment of gene drives likely affect the ability of future generations to use the natural world to ensure global health and well-being? (2) How would the deployment affect the ability of future generations to apply their own values to enjoy or appreciate the natural world? (3) How reversible is the deployment so that future generations could apply their own values to restore their options for use or nonuse decisions?

Ecosystems are complex and sensitive. Unintended effects could accompany the engineering of species with gene drives in the wild. For example, a more dangerous pest might fill a niche left vacant by a population suppression gene drive, or beneficial predators might be harmed from eating prey with killer-gene drives. Although researchers are working on systems to recall gene drives, certain effects could be irreversible, and others unpredictable. Thus, humanity’s ability to alter populations within ecosystems through genetic engineering raises issues associated with biodiversity and conservation that, in turn, may affect the abilities of current and future generations to use and enjoy the benefits of the natural world. Furthermore, there are important IE issues to consider from a non-use standpoint. Visions of the natural world may change over generations, and the attitudes of future generations toward having permanently engineered populations in their natural world need to be considered. Will future inhabitants of the planet view these species as wild ones? Will they cease to enjoy their surroundings if they know that the species are genetically altered or manipulated by humans?

Principles of IE should be incorporated into contemporary decision-making about whether, when, and how to deploy gene drives. The range of ethical issues will vary according to what the gene drive is designed to achieve in the organism, such as whether it will: (1) immunize a population against a health hazard or the ability to carry it; (2) decrease the organism’s fitness to suppress the population; (3) enhance or protect the population itself against threats; or (4) make the population newly susceptible to chemical or biological agent. IE issues will also differ according to broad purpose categories of improving agricultural production, protecting human health, controlling invasive species, or preserving endangered species.[3]

For example, applications of gene drives to human disease eradication and agricultural production primarily benefit the current generation with secondary benefits and potential risks to future generations. In these cases, the irreversibility and uncertainty surrounding the deployment may not be acceptable from the standpoints of conserving options, access, and quality associated with the environment. Perhaps in these cases, we should proceed cautiously and deploy gene drives only if uncertainties can be reduced and only with public dialogue to envision the concerns of subsequent generations. In contrast, there seems to be more latitude—and perhaps even an ethical imperative—to develop gene drive technologies for protecting threatened species, perhaps through a disease immunization approach. In this category, irreversibility and greater uncertainty might be tolerated in order to conserve the natural and cultural world for future generations, especially if alternatives to protect the species are not viable.

Next Steps

With increasing proposals for the use of genetic engineering in the wild, there is a strong argument to be made for consulting with the generations that are to inherit the world altered through this technology. A simple, first step to considering intergenerational equity issues in decision making could be a national effort to consult the next generation and report their concerns and hopes for gene drives back to policy makers.[4] The idea of “nature” and human relationships with it are shifting, and today’s youth are most likely to experience the changes we make today. Yet they are left out, and their voices are not heard by policy makers. As adults working in this area, we can at least provide opportunities for youth to discuss their hopes, concerns, and attitudes about next generation genetic engineering including gene drives, while we encourage policy makers to adopt a long-term perspective for other future generations.

[1] For example, see http://nas-sites.org/gene-drives/ and https://aeon.co/users/jennifer-kuzma.

[2] Brown Weiss, E. (1990). What Obligation Does Our Generation Owe to the Next? An Approach to Global Environmental Responsibility: Our Rights and Obligations to Future Generations for the Environment. American Journal of International Law. 84(198), 201–02.