Mirror life poses ‘unprecedented’ risk to life on Earth warns Nobel Prize-winning Cambridge scientist and colleagues

A Nobel Prize-winning Cambridge scientist is among a group of experts who have warned that the creation of mirror life could be catastrophic for life on Earth.

Sir Greg Winter and fellow world-leading scientists have called for a halt to work to create mirror-image bacteria as they would pose “unprecedented risks”.

They say the capability to create mirror life - using the mirror image of molecules found in nature - “is likely at least a decade away and would require large investments and major technical advances”.

But they note that “progress on key enabling technologies is under way”.

Writing a commentary in Science on their 299-page report, the group of 38 eminent scientists warn they are “deeply concerned”.

“Our analysis suggests that mirror bacteria would likely evade many immune mechanisms mediated by chiral molecules, potentially causing lethal infection in humans, animals, and plants,” they say.

“They are likely to evade predation from natural-chirality phage and many other predators, facilitating spread in the environment. We cannot rule out a scenario in which a mirror bacterium acts as an invasive species across many ecosystems, causing pervasive lethal infections in a substantial fraction of plant and animal species, including humans.

“Even a mirror bacterium with a narrower host range and the ability to invade only a limited set of ecosystems could still cause unprecedented and irreversible harm.”

All known life is described as ‘homochiral’, which refers to its ‘handedness’. Although the reasons are not understood, DNA and RNA are made from ‘right-handed’ nucleotides, while proteins are made from ‘left-handed’ amino acids - a reference to the direction in which polarised light skews when beamed through a pure solution of the molecule.

Although the mirror image of this could be just as functional as existing life, it cannot arise from it now.

The scientists explain: “Evolution proceeds in incremental steps and would be unable to invert the chirality of complex biomolecules such as DNA or proteins, let alone all biomolecules simultaneously.”

They add: “It is also exceedingly unlikely that we will encounter mirror life that has arisen independently. However, with scientific advances, a mirror organism might be created in a laboratory.”

Doing this would be a “far more complex feat of biological engineering than has ever been accomplished”, but the group notes: “Scientists are increasingly able to synthesise complex mirror-image biomolecules.”

With progress being made in synthetic biology, they anticipate that existing technological “barriers will be eroded as research progresses”.

And if mirror bacteria are created, they warn their growth outside of the laboratory is plausible.

They could “evade many immune defenses of humans, animals, and plants” and, in this nightmare scenario, they could replicate within a host body.

“Unchecked replication of mirror bacteria within internal tissues is likely to be deleterious to the host organism and may be lethal,” says the group, which also includes US scientists Dr Craig Venter, who led one of the first draft sequences of the human genome, University of Chicago Nobel laureate Prof Jack Szostak and Dr Kate Adamala, a synthetic biologist at the University of Minnesota who abandoned her work on creating a mirror cell after learning of the risks.

The scientists warn that once this particular genie is out of the bottle, there may be no way to get it back in, as mirror bacteria would “evade many forms of predation and microbial interference”.

They predict: “They would be intrinsically resistant to infection by natural-chirality bacteriophages, may be resistant to consumption by many predators, and may be resistant to most antibiotics produced by microbial competitors.”

The result could be an ecological Armageddon.

“Much like an invasive species with few natural predators, we are concerned that mirror bacteria could rapidly proliferate, evolving and diversifying as they spread. Persistent and potentially global presence of mirror bacteria in the environment could repeatedly expose human, animal, and plant populations to the risk of lethal infection,” they warn.

So why would anyone want to create a mirror bacteria? Curiosity has driven some of the work to date, along with plausible scientific and potential therapeutic applications for mirror biomolecules.

Mirror bacteria could be used to create these, or used as “a chassis for live cell therapeutics”, but other means of achieving these ends exist.

Any biocontainment or biosecurity efforts to try to control the spread of mirror bacteria are doomed to fail, the scientists warn.

“Countermeasures such as mirror antibiotics, crops engineered to be resistant to mirror bacteria, and mirror phages appear very unlikely to be sufficient to stop or reverse the spread of mirror bacteria throughout global ecosystems or to prevent unacceptable loss of life and irreversible ecological changes that could result,” they say.

“The primary challenge with these countermeasures is our inability to deploy them throughout the ecosphere at sufficient scale to prevent or counter dissemination and evolutionary diversification of mirror bacteria in the wild. They could therefore only protect against a fraction of the potentially immense harm.”

Instead, they call for “systems for monitoring the purchase of mirror oligonucleotides and precursors, and regulations and laws to prevent the creation of mirror life”.

They want to engage the scientific community in further discussion of the risks and they “recommend that research with the goal of creating mirror bacteria not be permitted, and that funders make clear that they will not support such work”.

They call for more work to be done on understanding how to avert the risk and conclude: “We are hopeful that scientists and society at large will take a responsible approach to managing a technology that might pose unprecedented risks.”

Sir Greg Winter, a former master of Trinity College who has conducted his research at the MRC Laboratory of Molecular Biology and MRC Centre for Protein Engineering in Cambridge, shared the Nobel Prize in Chemistry in 2018 following his pioneering work on therapeutic monoclonal antibodies.