What are gene drives? How they work, potential applications and risks

Gene drives are genetic systems that increase the probability that a particular genetic element will be inherited. This inheritance bias can allow a genetic trait to spread through a sexually reproducing population more readily than it would under typical Mendelian inheritance.

Gene drives occur naturally, but researchers can also engineer them using genetic technologies such as CRISPR-Cas9. Engineered gene drives are being investigated as potential tools for controlling disease-transmitting mosquitoes, invasive species and agricultural pests. However, their development also raises scientific, ecological, ethical and governance questions.

As of September 2026, no engineered gene-drive organism has been released into the environment. Research remains in laboratory and other contained settings.

What is a gene drive?

Under typical Mendelian inheritance, an organism carrying one copy of a particular genetic variant usually has a 50% chance of passing it to each offspring. A gene drive biases this process, increasing the proportion of offspring that inherit a particular genetic element.

Over successive generations, this inheritance advantage may allow the genetic element, and any trait associated with it, to become more common in a population. Whether this happens, how rapidly it occurs and how far the gene drive spreads depend on many factors, including:

• the design of the gene-drive system;
• the biology and reproductive behaviour of the target species;
• the fitness of organisms carrying the gene drive;
• the genetic diversity and structure of the population;
• environmental conditions;
• movement and mating between populations;
• the development of genetic resistance.

Gene drives are therefore not organisms themselves. They are genetic systems carried by organisms and designed, or naturally able, to influence inheritance.

How do gene drives work?

Gene drives work by increasing the probability that a genetic element is transmitted to offspring. Different gene-drive systems achieve this through different biological mechanisms.

Many engineered gene drives currently under investigation are CRISPR-based homing gene drives. These systems generally contain:

• the Cas9 enzyme, which can cut DNA;
• a guide RNA, which directs Cas9 to a specific DNA sequence;
• the genetic trait or other sequence intended to be inherited.

When an organism carrying a homing gene drive mates with an organism that does not carry it, the offspring initially inherit one chromosome containing the gene drive and one without it. In certain cells, the CRISPR-Cas9 system cuts the corresponding DNA sequence on the chromosome without the drive. The cell may then repair the cut by using the drive-containing chromosome as a template, copying the gene-drive construct into the cut site.

If this copying process is successful, the organism may pass the gene drive to considerably more than half of its offspring. The exact inheritance rate varies between gene-drive designs, species, sexes, genetic backgrounds and experimental conditions.

Not all gene drives use this copying mechanism. Other systems may bias sex ratios, disrupt genes required for reproduction, or use toxin–antidote mechanisms that favour the survival of offspring carrying the drive.

Are gene drives natural or engineered?

Gene drives are not exclusively human-made. Naturally occurring genetic elements that bias their own inheritance have been identified in organisms including fungi, fruit flies, mosquitoes and mice. These include homing endonuclease genes, meiotic drivers, segregation distorters and other selfish genetic elements.

Scientists have studied inheritance-biasing systems for decades. The emergence of CRISPR-Cas9 genome editing in the 2010s made it much easier to design genetic systems that target specific DNA sequences. A landmark paper by Esvelt et al. (2014) described how CRISPR could be used to develop RNA-guided gene drives and drew attention to both their potential applications and their possible ecological implications.

Since then, researchers have developed experimental gene-drive systems in several organisms, particularly mosquitoes and fruit flies. Research has also expanded in areas such as molecular design, population genetics, ecological modelling, risk assessment and governance.

What types of gene drive are being developed?

Gene drives can be classified in different ways. One important distinction concerns their intended effect on the target population.

Population modification

Population modification, also called population replacement or population alteration, aims to spread a trait through a population without necessarily reducing its size.

For example, researchers are investigating whether gene drives could spread traits that reduce the ability of Anopheles mosquitoes to transmit malaria parasites. The objective would be to make the mosquito population less capable of transmitting disease rather than to eliminate it.

Population suppression

Population suppression aims to reduce the size of a target population and, in some proposals, eliminate it from a particular area.

A suppression gene drive might:

• reduce female fertility;
• disrupt a gene required for reproduction;
• bias the sex ratio towards males; or
• reduce the survival or reproductive success of offspring.

Because these approaches act through reproduction, their effects would usually emerge across several generations rather than immediately after release.

Are all gene drives designed to spread indefinitely?

No. Gene-drive systems differ substantially in their expected ability to spread and persist.

Self-sustaining gene drives are designed to continue spreading once introduced, potentially from a relatively small initial release. Depending on their design and the biology of the target species, they may spread across connected populations and potentially across political borders.

Self-limiting or spatially limited systems are intended to restrict how long or how widely an intervention persists. Some require repeated releases, a sufficiently large initial introduction or the presence of particular genetic conditions within the target population.

These categories are not absolute. A gene drive’s behaviour cannot be determined from its design alone. Its spread will also depend on the characteristics of the organism, the receiving population and the environment. Modelling and laboratory evidence can inform predictions, but uncertainty will remain when considering how a system might behave under complex environmental conditions.

What could gene drives be used for?

Engineered gene drives are being explored for possible applications in public health, conservation, agriculture and animal health. These applications remain at different stages of research and should not be understood as established or currently available interventions.

Public health

Most advanced gene-drive research has focused on mosquitoes that transmit human diseases.

Potential applications include:

• suppressing populations of Anopheles mosquitoes that transmit malaria;
• modifying Anopheles mosquitoes so that they are less able to transmit malaria parasites; and
• investigating whether similar approaches could eventually be developed for other disease vectors.

The feasibility of a gene drive depends strongly on the biology of the target organism. Findings from Anopheles mosquitoes cannot automatically be transferred to Aedes mosquitoes, which transmit diseases such as dengue, Zika and chikungunya. The two mosquito groups differ in their reproductive biology, ecology, population structure and current state of gene-drive research.

Conservation and biodiversity

Gene drives have been proposed as possible tools for managing invasive species that threaten native biodiversity, particularly on islands.

One frequently discussed example is the potential use of gene drives to suppress invasive rodent populations. Rats and mice introduced to islands can prey on native birds, reptiles and invertebrates or compete with them for resources. Researchers have therefore investigated whether genetic biocontrol could complement existing control methods.

Any conservation application would require careful assessment of ecological effects, animal welfare, feasibility and the possibility of the modified organisms moving beyond the intended area.

Agriculture and animal health

Gene drives have also been proposed for managing insects that damage crops or affect livestock. Potential objectives include reducing pest populations, altering their susceptibility to pathogens or reversing resistance to existing control measures.

These applications remain largely experimental. Their practical feasibility would depend on the reproductive biology of the target species, movement between populations, resistance, regulatory requirements and comparison with available alternatives.

How are gene drives different from other forms of genetic biocontrol?

Genetic biocontrol includes several approaches that use genetics or inherited characteristics to manage harmful populations. Gene drives are one category within this broader field.

A well-established example is the sterile insect technique (SIT). In SIT programmes, large numbers of sterilised males are released into the target population. When these males mate with wild females, viable offspring are not produced. Repeated releases can therefore reduce the population over time.

SIT has been used successfully against several insect pests. One prominent example is the eradication of the New World screwworm from North and Central America through sustained releases of radiation-sterilised flies.

Gene-drive approaches differ because they are intended to bias inheritance. The genetic effect can therefore be passed to offspring and, depending on the system, continue spreading across generations.

Approach	Is the effect inherited?	Are repeated releases generally required?	Main intended outcome
Sterile insect technique	No	Yes	Population suppression
Self-limiting genetically modified insects	Limited to a small number of generations	Usually	Population suppression
Self-sustaining gene drive	Yes	Not necessarily	Population suppression or modification
Spatially or temporally limited gene drive	Yes, but designed to be restricted	Depends on the system	Population suppression or modification

The boundaries between these categories are not always simple, and proposed systems vary considerably in their design and expected behaviour.

What are the main scientific challenges?

Laboratory results do not by themselves show how a gene drive would behave in the environment. Important scientific challenges include:

Resistance

A gene drive may create or encounter genetic variants that it cannot recognise or modify. If these resistant variants have a reproductive advantage, they may become more common and prevent the drive from spreading or producing its intended effect.

Fitness effects

Carrying a gene drive may affect an organism’s survival, mating success or reproductive capacity. These effects can influence whether the drive spreads and how long it persists.

Genetic diversity

Target populations may contain DNA sequence variations that are absent from laboratory populations. A gene drive designed against one sequence may therefore work differently across geographical regions.

Population structure and movement

Populations are not uniformly mixed. Geography, seasonal changes, mating behaviour and migration can influence the movement of a gene drive between populations.

Ecological effects

Changing or suppressing a population could affect predators, competitors, food webs or ecosystem functions. The significance of these effects would depend on the organism, the receiving environment and the scale of the intervention.

Transfer beyond the intended population

A gene drive could potentially move into non-target populations of the same species through migration and mating. Transfer to closely related species may also need to be considered where hybridisation is biologically possible.

These challenges do not imply that every proposed gene drive will produce the same risks. Assessment needs to be case-specific and consider the particular organism, genetic construct, receiving environment and intended application.

What governance and ethical questions do gene drives raise?

Gene drives raise governance questions because some systems are intended to spread through wild populations rather than remain confined to individual organisms or release sites.

Important questions include:

• How should potential benefits and harms be assessed?
• What evidence should be required before field testing or environmental release?
• How should uncertainty and possible long-term effects be addressed?
• Who should participate in decisions about research and potential deployment?
• How should potentially affected communities be engaged?
• How should the knowledge, rights and interests of Indigenous Peoples and local communities be considered?
• How should countries coordinate when a gene drive could cross national borders?
• Who would be responsible for monitoring and responding to unexpected outcomes?
• How should gene-drive approaches be compared with existing alternatives?

Gene drives are discussed in international processes including the Convention on Biological Diversity and its Cartagena Protocol on Biosafety. In 2024, Parties to the Cartagena Protocol welcomed additional voluntary guidance materials to support the case-by-case risk assessment of living modified organisms containing engineered gene drives.

International discussions have emphasised risk assessment, precaution, scientific cooperation, capacity-building and the participation of potentially affected groups. However, decisions about research or possible use would also be shaped by national laws, regulatory systems and local contexts.

Have engineered gene drives been released into the environment?

As of September 2026, no engineered gene-drive organism has been released into the environment.

Gene-drive research has primarily taken place in laboratories and other contained facilities. No gene-drive product is currently available for routine use in public health, conservation or agriculture.

This distinction is important because researchers have conducted field releases of other genetically modified or sterilised insects. Those insects should not automatically be described as gene-drive organisms. For example, releases of self-limiting genetically modified mosquitoes and sterile insects do not constitute environmental releases of engineered gene drives.

Before any proposed field testing or environmental release, developers and decision-makers would need to consider the applicable regulatory requirements, risk assessment, monitoring, public engagement and the views of potentially affected communities.

Why is gene-drive research important?

Gene drives could offer new ways to address difficult problems involving disease vectors, invasive species and agricultural pests. Their ability to act at the population level distinguishes them from interventions directed only at individual organisms.

The same characteristic that makes gene drives potentially useful (their capacity to spread inherited traits) also makes their development scientifically and politically complex. Outcomes may extend across generations, ecosystems and national borders.

For this reason, gene-drive research involves much more than molecular biology. It also requires expertise in ecology, evolutionary biology, population genetics, mathematical modelling, risk assessment, public health, conservation, ethics, law, governance and community engagement.

Research should therefore examine not only whether a gene drive can work, but also:

• whether it is needed;
• whether it is likely to provide the intended benefit;
• how it compares with available alternatives;
• what harms or unintended effects might occur;
• whether those effects can be monitored or managed; and
• who should participate in deciding whether development should proceed.

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Frequently asked questions (FAQs)

What is a gene drive in simple terms?

A gene drive is a genetic system that increases the likelihood that a particular genetic element will be inherited. This inheritance advantage may allow an associated trait to become more common in a sexually reproducing population over several generations.

Are gene drives the same as gene editing?

No. Gene editing changes DNA at a selected location. A gene drive affects how a genetic element is inherited. Many engineered gene drives use gene-editing tools such as CRISPR-Cas9, but gene editing does not necessarily create a gene drive.

Are gene drives genetically modified organisms?

Engineered gene-drive organisms are genetically modified organisms. Naturally occurring gene-drive elements, however, are not human-made genetic modifications.

Do all gene drives use CRISPR?

No. Gene drives occur naturally through several biological mechanisms, and engineered systems can use different designs. CRISPR-Cas9 is widely used in current research because it allows researchers to target particular DNA sequences.

Will a gene drive always spread through an entire species?

No. Spread depends on the gene-drive design, its effects on fitness, the biology of the species, genetic resistance, mating patterns, migration and connections between populations. Some systems are specifically intended to be geographically or temporally limited.

Can gene drives move between species?

Gene drives normally spread through reproduction and therefore require mating and viable offspring. Transfer to another species would generally require hybridisation with a closely related species. Whether this is possible must be assessed for the particular organisms involved.

Could a gene drive eliminate a species?

Some suppression systems are designed to reduce a target population and could, in theory, cause local elimination. This does not necessarily mean global extinction. The outcome would depend on the drive, the species, population connectivity, resistance and environmental conditions. Such claims require careful case-specific analysis.

What are gene drives being developed for?

Proposed applications include controlling malaria-transmitting mosquitoes, managing invasive species that threaten biodiversity, and controlling agricultural or livestock pests. These applications remain under research and are at different stages of development.

What are the principal concerns about gene drives?

Concerns include genetic resistance, unintended ecological effects, spread beyond intended populations, uncertainty about long-term outcomes, cross-border movement, animal welfare, public participation and the adequacy of regulatory and governance systems.

Have gene drives been used in the wild?

No engineered gene-drive organism had been intentionally released into the environment as of September 2026. Research remained in laboratory and other contained settings.

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Additional scientific, policy and regulatory materials are available in the External Resources section.

Last scientifically reviewed: September 2026.