Could the next breakthrough pesticide be rewriting our genes without us knowing?
- Gene-silencing RNAi pesticides promise precision but could quietly alter ecosystems—and even impact human genes.
- Already in our food, these minimally regulated compounds slip through safety checks, raising red flags about hidden genetic risks.
- Experts warn we’re part of an “open-air genetic experiment,” urging immediate action to prevent unintended, far-reaching consequences.
Imagine a technology that could genetically rewire organisms in real-time, silencing critical genes across entire ecosystems with unknown effects. Sounds like science fiction? It’s not. It’s the reality of a new class of pesticides harnessing RNA interference–or RNAi–and they’re already being deployed in our fields and food supply with minimal testing or oversight. According to organic producers and non-GMO (genetically modified organisms) advocates, the risks could be catastrophic.
Environmental Organization Warns of RNAi Pesticide Dangers
In 2020, a groundbreaking report from Friends of the Earth (FOE) rang the alarm on the dangers posed by gene-silencing RNAi pesticides. According to the non-governmental environmental organization report, these products can genetically modify organisms in the open environment, with risks of unintended effects on non-target species, human health, and the integrity of organic and non-GMO agriculture. Despite these threats, RNAi pesticides face little to no regulatory scrutiny in most countries, and some have already been approved for use.
In June 2017, the U.S. Environmental Protection Agency green-lit the RNAi corn developed by Monsanto and Dow, now being marketed under the trade name SmartStax Pro.
In a press release announcing the approval of SmartStax Pro, regulators praised the product for its value to the farmer and the low impact it has on the environment.
“The ribonucleic acid interference (RNAi) technology found in SmartStaxPro works through a process of gene control that occurs naturally in plants, animals, and humans alike. Scientists harnessed this control process to create the product, which works as a pesticide by silencing or turning off the activity of a gene critical to corn rootworm survival, resulting in the death of the corn rootworm. This product is so specific that it only affects the corn rootworm,” states the Environmental Protection Agency (EPA) press release.
RNAi works by using small RNA molecules to interfere with and “silence” the activity of specific genes. While that may sound precise, the FOE report emphasizes that RNAi technology is prone to “off-target effects,” meaning it can unintentionally silence genes in non-target organisms. Since many genes are conserved across species, a pesticide designed for one insect could end up harming beneficial pollinators, soil microbes, or even humans. What’s more, the alteration caused by RNAi can sometimes be passed down to future generations, meaning that a single application could spark uncontrollable ripple effects.
The Friends of the Earth report dubs RNAi pesticides “a vast, open-air genetic experiment,” with entire ecosystems at risk. Because they’re sprayed directly into the environment, controlling exposure is nearly impossible. Any organism that takes up the interfering RNAs could have its genome tinkered with. Some evidence suggests that ingesting RNAs from our diet may even influence human gene expression.
There’s also a risk that RNAi sprays could alter the genetic makeup of the very crops they’re meant to protect, changing nutritional content or toxicity in unpredictable ways.
Could RNAi Pesticides Impact Human Genes?
What’s particularly concerning is that the off-target effects of RNAi pesticides may extend beyond the farm and into the bodies of consumers. A 2008 study funded by Monsanto revealed that numerous small RNAs from corn, soybeans, and rice had perfect sequence complementarity to human genes. While Monsanto pointed to this finding as evidence of safety, the reality is far more complex and troubling.
As the study showed, there are numerous plant RNAs with sequences identical to human genes. If these dietary RNAs are indeed able to influence human gene expression, as mounting evidence suggests, then the genetic rewiring of our food crops with novel RNAi molecules could have far-reaching and entirely unpredictable effects on our health.
A 2012 study published in Cell Research demonstrated that a specific plant microRNA from ingested rice could be detected in human blood and tissues. When the same plant microRNA was fed to mice, it appeared to modulate the expression of a receptor involved in removing LDL cholesterol. If a natural plant RNA can have such a significant biological effect, what might be the consequences of engineered RNAi molecules?
Many genes are not consistently expressed, and their activity can vary based on environmental conditions. This adds yet another layer of complexity and unpredictability when it comes to assessing the risks of RNAi crops.
Furthermore, the human gut is home to a diverse community of microbes that play a vital role in our health and immune function. Preliminary research suggests that some of these bacteria may be capable of taking up dietary RNAs and incorporating them in such a way as to affect their gene regulation. The effects of RNAi crops on the human microbiome are unknown but could be significant given the importance of gut flora in everything from nutrient absorption to mental health.
Taking Advantage of Loose Regulations
In the United States, the EPA’s regulatory framework for genetically engineered crops was established in 1986 and has only been updated once in the last 30 years.
This old standard is being used to evaluate a whole new kind of pesticide. SmartStaxPro, the RNAi corn developed by Monsanto and Dow, produces a double-stranded RNA that disrupts a critical gene in a major agricultural pest, the western corn rootworm, causing its death. In 2023, the EPA registered an RNAi pesticide that targets the Colorado potato beetle.
According to the FOE report, the companies crafting RNAi pesticides are also filing broad patents that would grant them ownership rights over any organism exposed to their products. This could mean that if a farmer’s crops are unintentionally contaminated by drifting RNAi sprays, the company could lay claim to their harvest.
At the international level, RNAi is barely on the regulatory radar. Technically, RNAi products fall under the “living modified organisms” category defined in the Cartagena Protocol on Biosafety. According to one assessment published in the Annual Review of Plant Biology, “the European GMO regulatory framework is inadequate and needs to be updated.”
For organic and non-GMO advocates, this regulatory vacuum is a recipe for disaster. Without robust safety testing and labeling requirements, RNAi crops could soon infiltrate food supplies worldwide, turning consumers into unwitting test subjects in a massive uncontrolled experiment. Organic farmers may find their crops and local ecosystems irreversibly contaminated by drifting RNAi molecules.
Can We Prevent an Agricultural Disaster?
Despite these concerns, many consumers may already be eating this genetically altered corn. There is significant adoption of these advanced corn traits, particularly in regions where corn rootworms are prevalent. Based on recent information from Bayer, their SmartStax and SmartStax PRO traits are utilized in about 15 million acres across the United States–nearly 17 percent of the ninety million acres dedicated to corn growing in the United States.
An email was sent to Bayer Crop Sciences requesting comment on the FOE report and the threat of off target consequences related to their RNAi pesticides. No response was returned.
Although advocates for RNAi pesticides promote it as a precise means for targeting a single pest, it’s clear the technology isn’t merely a tweak to existing agricultural practices–it represents a watershed moment in the industrialization of our food supply.
A review of RNAi transgenic plant technology from the Bioscience Resource Project, notes several off-target effects the technology has demonstrated. The report suggests that this technology could lead to “distinct toxicological and environmental hazards.”
“… while RNAi holds great promise for agricultural applications, the potential for OTEs within the plant, in non-target organisms, and in mammals consuming the plant material warrants careful assessment and risk mitigation strategies,” state authors Jonathan R. Latham and Allison K. Wilson.
To mitigate these risks, researchers propose several preconditions for regulatory approval of RNAi transgenes, such as avoiding perfectly duplexed sequences, minimizing complementarity with known human and host sequences, ensuring minimal transgene expression levels, and using short RNAi-triggering sequences and naturally occurring miRNA (microRNA) promoters.
Until these off-target effects can be identified and eliminated, the report calls for “a precautionary approach” to furthering the technology and asks regulators to consider the possible hazards the development of RNAi-based genetically modified crops may cause.
With regulations as they now stand, biotech firms are granted the power to deliberately manipulate gene expression across entire species and ecosystems. Although the technology may be billed as a high-tech solution to move away from toxic pesticides, it is introducing a wide range of potential unintended adverse effects.
