Unlock the Editor’s Digest for free

The writer is leader of the Synthetic Biology Group at the J Craig Venter Institute

This year I witnessed something I never expected to see in my scientific career: more than 150 scientists, policymakers, science funders and ethicists came together at the Institut Pasteur in Paris seeking to prevent a global threat that does not yet exist.

Within the next few decades, scientists will probably be able to build mirror life — organisms built from molecular components that are mirror images of the versions used in nature.

I am a synthetic biologist. Engineering cells and bacteria is my trade. I was part of the team that, in 2010, created the world’s first living bacterial cell with a chemically synthesised genome. For decades, my colleagues and I have sought to scale the beneficial applications of this technology, helping to create vaccine strains, biofuels, pharmaceuticals and other molecules that could create new sources of clean energy, cure diseases and clean up the planet.

Mirror life represents a profound break from this work. It would be created using entirely different building blocks, not the same molecules that are found in all known life. The organism’s DNA would twist to the left where ours twists to the right; their ribonucleic acids, essential to biological functions, would loop and bulge in the opposite direction.

Research into mirror cells has only been a tiny part of synthetic biology. But efforts to build a mirror ribosome — the cell’s protein factory — are under way. Once it is possible to build a mirror cell, it would be comparatively easy to engineer many more kinds of mirror bacteria — the simplest form of mirror life.

If this is achieved and Pandora’s box opens it could pose extraordinary risks. Mirror bacteria could evade our immune systems, confound our medicines and escape many of nature’s checks and balances.

To the best of our knowledge, our immune systems produce very weak antibody responses against mirror molecules, if any. Having even one immune deficiency can cause a patient to die of overwhelming bacterial infections; a mirror bacterial infection might be like having many immune deficiencies at once.

In the environment, predators including viruses and amoebae control bacterial populations. Mirror bacteria would be resistant to many of these predators. With fewer constraints, they could spread across ecosystems, disrupt food chains and cause fatal infections across species. Contaminated areas could become irreversibly uninhabitable, compromising our agriculture and natural world. Huge numbers of people, animals and plants could be wiped out, with some driven to extinction.

We have realised these dangers well before the point of no return. The Paris conference was a historic gathering: the first time scientists, ethicists, science funders and experts from the WHO and the UN came together specifically to discuss the threat from mirror life. 

Many argued that we need regulation and law to ensure that it is not created. I agree. This will require precision about what research can continue and what should cease. Some research could make it easier to create useful drugs, for example. Each major technological breakthrough offers a chance to assess whether going further increases the risks to people and the planet.

However, developing laws can require years of deliberation. Funding agencies can help create concrete barriers today. The Alfred P Sloan Foundation has already made clear that it will not support research with the goal of creating mirror organisms. Similar commitments from other funders would send a powerful message.

Over the next year, stakeholders will meet at the US National Academies of Sciences, Engineering and Medicine, the University of Manchester, the National University of Singapore, Rikkyo University in Japan, Harvard University, Yale University and elsewhere to try to establish these boundaries. What technical milestones towards mirror life require red lines that protect people and planet, while preserving the benefits of synthetic biology that have nothing to do with mirror life?

This moment echoes the best of scientific responsibility, such as when researchers recognised the ozone crisis and united to ban chlorofluorocarbons. We have an even rarer opportunity now to prevent a global threat before it causes any harm. The solution is clear: we should choose not to build mirror life and pass laws to ensure nobody can. The question is not whether we are able to prevent this threat — it is whether we will act while we still can.