A group of 38 leading biologists has issued a stark warning about the potential dangers of creating “mirror life“. Within the next few decades, scientists may be able to synthesize microbes built from mirror-image molecules, posing risks that could lead to unstoppable pandemics, massive crop failures, or the collapse of entire ecosystems.
Jack W. Szostak, a Nobel laureate and chemist at the University of Chicago, underscored the gravity of the situation: “The consequences could be globally disastrous.” He, along with his colleagues, authored an extensive 299-page technical report assessing the risks associated with this groundbreaking research. In a commentary published in the journal Science, they cautioned that an organism developed using this new technology could result in “extraordinarily damaging consequences for the environment, agriculture, and human well-being.”
At the heart of these concerns is the concept of “mirror life“. The molecules that make up DNA and proteins typically exist in one of two mirror-image forms: left-handed and right-handed. In all known life forms on Earth, DNA is made up of right-handed molecules, while proteins are made up of left-handed amino acids. Scientists are still unraveling why evolution favored this particular arrangement, but it’s clear that a mirror cell-with left-handed DNA and right-handed proteins-could theoretically perform all the biochemical reactions necessary to sustain life.
Recent advances have brought this theory closer to reality. Chemists have learned to make mirror proteins by assembling right-handed amino acids to create counterparts to the natural proteins found in our bodies. These mirror proteins function similarly to their natural counterparts, but have the notable advantage of being more resistant to degradation. Natural enzymes designed to break down left-handed proteins have difficulty interacting with these mirror versions. This property has spurred interest in the development of long-acting drugs for diseases such as HIV and Alzheimer’s.
In 2022, researchers Yuan Xu and Ting Zhu at Westlake University in China made significant progress by creating mirror enzymes capable of producing mirror RNA molecules from mirror genes. Such breakthroughs suggest that scientists could potentially assemble all the components needed to build a mirror cell within the next decade or two.
The prospect of making a mirror cell is undeniably intriguing. “If we made a mirror cell, we would have made a second tree of life,” said Kate Adamala, a synthetic biologist at the University of Minnesota. Beyond the scientific intrigue, mirror cells could have practical applications, such as producing improved mirror proteins for medical use.
But the potential dangers cannot be overlooked. Kevin Esvelt, a biologist at MIT, began to seriously consider the risks as the possibility of creating mirror life became more tangible. He discussed his concerns with biosecurity experts, which led to a collaboration of scientists from diverse fields, including immunology, plant biology, and evolutionary biology. Their collective findings painted a disturbing picture.
Mirror cells could bypass many of the natural barriers that keep organisms in check. The human immune system detects pathogens using molecular sensors that recognize left-handed proteins and right-handed DNA and RNA. A mirror cell infecting humans could evade these defenses altogether and proceed without triggering an immune response. “Ultimately, that host will be overrun, and that will be fatal,” warned Vaughn Cooper, an evolutionary biologist at the University of Pittsburgh.
The threat goes beyond human health. Animals and plants rely on similar mechanisms to fend off pathogens, and their systems would likely be ineffective against mirror organisms. Jonathan Jones, a plant biologist at the Sainsbury Laboratory in Norwich, England, highlighted the agricultural risk: “Essentially, all plants in the world would be unable to detect these bacteria.” An environmental release, even an accidental one, could lead to mirror cells dominating ecosystems because natural predators and viruses wouldn’t recognize or consume them. Deepa Agashe, an evolutionary biologist in India, expressed concern about the ecological impact: “The impact on the food chain would be devastating.”
Compounding the problem is the potential for mirror cells to mutate and evolve unpredictably once they begin replicating. Ruslan Medzhitov, an immunologist at Yale University, underscored this uncertainty: “Then all bets are off. You can’t predict what will happen.”
Recognizing these significant risks, some scientists have already changed their research focus. Dr. Adamala and her team decided to stop their work on mirror cells. “We’re saying, ‘We’re not going to do it,’” she said. The collective call from these leading scientists is clear: pause the pursuit of “mirror life” until its safety can be assured.
Filippa Lentzos, a biosafety expert at King’s College London, praised the proactive approach: “Sharing these conclusions with the public and calling for a broad discussion is a role model of responsible science today.” The situation presents a critical opportunity for a global discourse on the ethical and safety implications of such revolutionary research.
