Extinction by design: Should we genetically erase harmful species?

Should humans ever pull the plug on a living species? Advances in genome editing make that possibility concrete, and a recent study asks when, if ever, such power is justified.

The researchers weighed the suffering caused by pests against the intrinsic worth of biodiversity, setting a high bar for intentional wipeouts. Their conclusion is that genetically erasing a species might be acceptable, but only under exceptional, tightly bounded circumstances.

When erasing a species feels necessary

“This question keeps conservationists up at night,” said Dr. Clare Palmer of Texas A&M University after helping draft the report. She and colleagues argue that an animal’s capacity to cause widespread agony can, in rare cases, outweigh its right to persist.

Ethicists usually treat biodiversity as a moral good, yet real-world conflicts force tough trade-offs. When an insect’s life hinges on a calf’s ability to survive, abstract principles meet muddy pens and medical bills.

Most philosophies rank individual suffering above abstract species value once pain passes a certain threshold. Even ecologists concede that leaving sentient creatures to suffer avoidable harm strains any theory of non-intervention.

Three cases in focus

The parasitic screwworm (Cochliomyia hominivorax) burrows into the flesh of livestock and wildlife, killing thousands of animals every year before treatment can begin. The United States eliminated native populations in 1966 using the Sterile Insect Technique (SIT).

Mosquitoes of the species Anopheles gambiae spread malaria, a disease that took an estimated 597,000 lives in 2023 alone – most of them children under five.

Those numbers eclipse fatalities from many better-publicized illnesses and keep public-health agencies searching for stronger tools.

On South Africa’s Marion Island, the humble house mouse (Mus musculus) has started gnawing seabird chicks alive, pushing several albatross species toward local collapse. Conventional traps fail on rugged slopes, and poison risks collateral damage to native invertebrates.

How scientists can erase species

The Sterile Insect Technique remains the standard for humane pest control. Irradiated males mate but produce no viable young, gradually crashing the target population without pesticides.

A newer option, the gene drive, moves lethal or sex-skewing genes through wild populations so quickly that normal inheritance rules break down.

Researchers working with rodents have already demonstrated systems that turn almost every embryo male, guaranteeing eventual collapse.

For mosquitoes, scientists can now couple a drive to a gene that blocks parasite replication, reducing disease transmission rather than eliminating the insect outright. Palmer’s team notes that such restraint might satisfy the same moral aims with less ecological upheaval.

Killing pests sometimes gains approval

“Together, we argue, these cases suggest that deliberate full extinction might occasionally be acceptable, but only extremely rarely,” the authors wrote. Where pests impose unrelenting misery on humans or endangered wildlife, even cautious ethicists lean toward eradication. 

In farm economies, screwworm outbreaks once cost ranchers hundreds of millions of dollars each year.

The sterile-fly program reduced those losses while sparing cattle surgeries and antibiotic use, making SIT a textbook case of net welfare gain.

Risks and safeguards

No drive can be recalled once released. If a sex-skewing construct escaped from an island to a mainland, the entire species could vanish before regulators reacted. That possibility drives calls for redundant containment layers and staged testing.

Wild genomes hold surprises such as mating behavior, migration corridors, or hidden ecological roles.

Removing a dominant mosquito might allow a harder-to-control sibling species to fill the gap, canceling health gains while shackling communities to continuous editing cycles.

Governance frameworks must also weigh cultural values. Some communities view rats as food, while others see them as vermin. A one-size rule will not work in global treaties.

Who should decide to erase a species?

Palmer and colleagues insist that village councils, livestock owners, conservation NGOs, and public health officials should share equal seats at the table. Only broad consent can legitimize an action that removes a lineage that is millions of years old.

The study suggests that formal benefit-harm ledgers need to be updated as new data emerge. There is also a need for sunset clauses that halt projects if early milestones falter. Robust monitoring budgets must be in place before the first transgenic egg hatches.

Funding streams pose another dilemma. Genome projects often depend on philanthropic donors from far away. Affected regions need guaranteed control over long-term stewardship, including the power to veto deployment.

The fast pace of technology

Current international regulations lag behind the pace of synthetic biology. While conventions like the Cartagena Protocol aim to manage genetically modified organisms, they do not directly address deliberate extinction by gene drive.

This leaves a grey area where cross-border impacts, like species drifting across national boundaries, may not fall under clear legal control. Coordinated policy development is needed to prevent gaps that bad actors or accidents could exploit.

The World Health Organization and United Nations Environment Programme have both called for more robust oversight. However, the tools available for enforcement are often limited to guidance rather than mandates, leaving implementation up to individual nations.

The researchers say it’s critical to close these gaps before large-scale extinction drives become common, especially given how rapidly the technology is evolving.

The future of gene drives

CRISPR keeps shrinking the cost and time required to build custom drives, so ethical debates must stay a step ahead of lab capacity.

Palmer hopes that clear rules will prevent both reckless releases and sweeping bans that deny relief to suffering animals. She sees the conversation itself as a sign of progress.

Past generations used lead arsenate or DDT with little scrutiny. Today, genetic strategies face hard questions before a single insect leaves quarantine.

The study is published in the journal Science.

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