The story of mirror life: From intriguing idea to unprecedented threat

In the coming decades, we might figure out how to make an entirely new kind of life: a mirror cell, in which every molecule is the mirror image of those found in normal cells. Such reversed cells have probably never existed on our planet in its 4.5-billion-year history. Yet we could one day make them – perhaps as a way to make new drugs, or simply out of pure scientific curiosity about the origins and evolution of life.

But should we? According to a coalition of synthetic biologists and biosafety specialists, the answer is a resounding “no”. Mirror life, they argue, would pose “unprecedented risks” to the health of every living organism on the planet. If it got out, we might never be able to recapture it, leading to “pervasive lethal infections”.

It’s an apocalyptic-sounding threat, but would it really be as dangerous as the team argues if we managed to create these new life forms? And although mirror life could be decades away, could there be things we can do now to reduce the risk?

Many of the essential molecules of life can exist in two mirrored forms, like a person’s left and right hands. While these “chiral” molecules are difficult to distinguish from each other, their distinct shapes cause them to behave differently. No matter how much you rotate a left-handed molecule, you will never get it to match a right-handed one.…