Leading scientists have issued an urgent warning over the 'unprecedented' risk posed by a lab-made life which could wipe out mankind.
So-called 'mirror life' are synthetic organisms that are constructed out of mirrored versions of the molecules found in nature.
Experts warn that these mirror organisms would be 'invisible' to life on Earth, allowing them to slip past the immune defences of all known organisms.
If mirror bacteria were to escape from the lab, there would be nothing to prevent them from establishing themselves in the wild and threatening plants, animals, and humans with lethal infections.
The creation of mirror bacteria is at least a decade away but, in a 300-page technical review published in Science, the authors note that rapid progress is already being made.
A group of 38 Nobel laureates and other experts, including some who have previously tried to create mirror life, are now calling for a pause on all new research.
Dr Vaughn Cooper, a microbiologist from the University of Pittsburgh and co-author of the paper, says: 'This form of life has never existed or evolved, consequently, all biological interactions would be different or likely wouldn’t work.
'We don’t want to limit that promise of synthetic biology, but building a mirror bacterium is not worth the risk.'
Just like your left hand is a mirror image of your right, many biological molecules also have a left and right-handed mirror molecule.
What makes this feature so important for biology is that it doesn't vary from species to species - the molecules which make up all life on Earth have the same handedness.
For example, the spiralling double-helix of the DNA is right-handed whereas proteins are made up of left-handed amino acids.
Yet, as far as scientists can tell, the fact that our DNA is right-handed is an evolutionary fluke and there is no reason that life might not have evolved out of mirrored components.
So, although mirror life cannot evolve from life as we know it, scientists believe it is possible to create an organism in which all the biological molecules are mirrored.
What would make this so risky is that life on Earth has only evolved to deal with one shape of molecule.
Co-author Professor Gregory Winter, a Nobel prize-winning biologist from the University of Cambridge, told MailOnline: 'The risk of mirror life, in particular mirror bacteria, is that living organisms would not recognise their mirror counterparts as “foreign” and would not have the natural defences to protect themselves from attack by them.
'For example, humans would struggle to make antibodies against the mirror bacteria and be unable to control an infection. Similar arguments apply to all other living organisms, including plants under attack by mirror bacteria.'
Likewise, bacteria's natural predators also rely extensively on the handedness of their prey's molecules to kill bacteria.
This means there is nothing to stop rogue mirror bacteria from escaping into the wild and breeding without control.
The authors write: '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 if humans do find a way to defend themselves from this new threat, mirror bacteria could still destabilise large parts of the world's ecosystem.
Co-author Dr Nicholas Talbot, a plant disease expert and executive director of the Sainsbury Laboratory told MailOnline: 'It seems very likely that a mirror bacterium would be able to infect some plants.
'If major food crops were susceptible, the impact would be devastating — alongside the other effects.'
The good news is that the technology to create mirror life is still far off.
In their paper, the authors note that there have been significant breakthroughs in the creation of mirror molecules and the construction of artificial cells.
However, creating synthetic molecules is extremely expensive and would require massive breakthroughs in the field of synthetic cell research.
Dr Talbot says: 'The technical hurdles to create mirror bacteria are significant, so this is probably at least a decade away from being possible, but we felt sufficiently concerned about the risk that we wanted to establish public discourse on this long before it became a reality.'
The researchers are calling for greater scrutiny of their research and conclude that, unless compelling evidence emerges to the contrary, mirror bacteria must not be created.
While there are some possible benefits of mirror bacteria, such as biological drug synthesis and medical applications, the authors argue that the risks are not worth it.
Dr Cooper concludes: 'It would require enormous effort to build such an organism but we must stop that progress and have an organized, inclusive dialogue about how to effectively govern this.'
