'Tis the season for scary movies. One of our favorite genres is “science experiments gone awry,” including the rich world of fictional human/insect hybrids, creature features of all denominations, and, of course, Frankenstein. These are some of the images that populate streets and screens each Halloween.

So where does the line between science and science fiction lie? Are there really “mad scientists” at work in the land of genetic engineering? In an age when turbulent news cycles regularly keep us up at night, how scared of new GMOs should we be? Let’s unpack some of the risks, the blind spots, and the unintended consequences of the latest feats of genetic engineering.

Friendly mosquitoes: These suckers are friendly. A little too friendly.

While horror movies often depict flashy predators like sharks, monsters, or aliens, the deadliest creature on earth is actually the mosquito. Their danger lies in their ability to spread diseases such as malaria and dengue fever through bites. With the death toll for mosquito-borne illnesses estimated at around 725,000 people per year, reducing the mosquito population is an understandable ambition. 

From 2013 to 2015, it was this idea that led British biotech firm Oxitec to release tens of millions of genetically modified “friendly” mosquitos in Jacobina, Brazil. Oxitec engineered the mosquitoes to include a “self-limiting gene [that] prevents offspring of [the] released male insect[s] from surviving to adulthood.” After the genetically modified males mate with the local females, their offspring are, in theory, too weak to breed — causing a drastic reduction in the population. In the year after the release, there was a steep population drop. But something happened then that Oxitec did not intend: The offspring of the engineered male mosquitoes and the native female mosquitoes survived in far greater numbers than their engineers had imagined. According to a controversial recent study, the population recovered within 18 months, and genetic material inherited from the GMO mosquito is now present in up to 60 percent of the local population.

What are the long term consequences of this experiment? No one knows for sure. “It is the unanticipated outcome that is concerning,” said Jeffrey Powell, one of the study’s senior authors. Some scientists speculated that the new hybrid could now have an evolutionary advantage, making them more robust. And, while mosquitoes are dangerous as vectors of disease, they’re also a valuable food source for birds, bats, and amphibians — a sudden reduction, no matter how well-intended, could have ripple effects throughout the ecosystem.  This much we do know: We are in uncharted territory with the deadliest creature on earth.

Don’t have a GMO cow

Horns can be fearsome weapons. Due to the close quarters of animals in commercial cattle farms, horns are frequently removed for safety. It’s a widespread yet controversial practice: Horns are made of living tissue and contribute to respiratory and digestive functions, amongst other things. Because the gene that determines hornlessness is dominant, selective breeding is a reliable natural option.

Despite the low-tech solutions already available, biotech firm Recombinetics produced a genetically engineered hornless bull using a new gene editing technique called TALEN. A routine test run by the FDA later revealed that the GMO bull and its offspring were carrying non-bovine DNA. Antibiotic-resistant lab material had been integrated into the cell as it repaired itself.

There are several causes for concern: 

• First and foremost, there is a profound dissonance between what was promised and what was delivered. TALEN is part of a suite of new genetic engineering techniques described by the National Institute of Health as ”effective and reliable tools for genome engineering.” When these tools are marketed for their precision, the layperson could reasonably infer that TALEN is safe and reliable, which is not necessarily the case. According to Heather Lombardi, Director of Animal Bioengineering at the FDA: “When you create a DNA break, and that could be with a genome edit, the cell wants to repair itself. Ideally, it will repair itself correctly. But it can also integrate any DNA that’s around. There’s that potential.” 
• Also of concern is the fact the company that engineered the hornless bull didn’t discover the error. Rather, it was uncovered by chance at the FDA. This is troubling because it indicates a blind spot for testing and safeguards in the production of genetically engineered animals. 
• Because hornless cattle are already produced through selective breeding, genetically engineered hornless cattle and their offspring are subject to lower safety standards than other GMO animals. The argument is that they are identical to the naturally bred animals (or, they would be if there wasn’t random lab junk attached to their DNA), so they can be “generally regarded as safe” — a designation so casual you can practically hear the shrug.

What does this mean for the future of genetically modified cattle? As is the case with unexpected outcomes, we don’t really know. It’s been reported that the extra DNA is “unlikely” to cause problems in the cows. What a relief. We can only hope the same is true next time it happens, or the time after that. One study found “multiple instances of this type of error in other experiments. According to an article in the New Food Economy, “those integration errors are often not major findings, leading Lombardi and Norris[note] Heather Lombardi, Director, Division of Animal Bioengineering and Cellular Therapies, FDA, and Alexis Norris, the FDA bioinformatician who discovered non-bovine DNA in Recombinetic’s genetically modified cattle.[/note] to suspect that they’re underreported or overlooked.”

The proverbial “bull in a china shop” will still break everything, whether it has horns or not.

Scary stories rely on recurring themes: a deadly (and probably ugly) monster in pursuit of a plucky (and probably attractive) protagonist. Our real-life scary stories also have recurring themes: “precise” gene editing experiments with unexpected outcomes; corporations that are unaware of the aberration; and uncertain long term consequences.

We are at a critical point in our species’ journey. In the last century, the human race’s power surpassed its wisdom to the extent that our industriousness now threatens the survival of the planet. By acting beyond the scope of natural and evolutionary safeguards, we risk introducing the unknown into already brittle ecosystems. Given the interconnectedness of the global food system, the scale of the potential damage, and the already compromised state of the environment, caution should outweigh hubris A basic truth of horror films is that no one should venture into a creepy basement alone. To prevent real-life monsters, surely the building blocks of life should not be rearranged and served up for dinner. At the Non-GMO Project, we stand with a growing movement of concerned citizens yelling, “Don’t go there!”