It could revolutionize human health — or it could spell our doom. It really depends on who you ask. I’m not talking about potentially risky biodefense lab research, but something that doesn’t yet exist: mirror life.

Here’s a refresher on normal biology: the cells in our bodies are composed of the building blocks of life. Nucleotides and sugars make up our DNA, which provides the blueprint for cells and codes for proteins that carry out key biological functions. In all of life, these biomolecules have a specific “handedness.” (Bear with me here.)

A mirror image is possible, the way your left and right hands are mirror images of each other. But mirror life can’t evolve from existing life in nature. If it eventually emerges, it’s because we’ve created it.

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Think of life as we know it as a vinyl record. We listen to the A-side, with genetic material made from right-handed nucleotides and proteins composed of left-handed amino acids. Natural life has evolved to only use this configuration. These biomolecules are chiral: they can’t be superimposed on their mirror images. All life uses the same chirality. The hope, and fear, is that the opposite — synthetic life based on left-handed genes and right-handed proteins — exists on the bonus B-side of the record.

As my former colleague Kelsey Piper explained back in January, mirror life could represent a whole new way that the world could end.

We’re at least decades away from being able to create entire mirror cells — that includes bacteria. The technologies that would allow us to do so aren’t yet up to the task. But we’ve encountered mirror biomolecules like right-handed amino acids in nature, and scientists have synthesized mirror enzymes capable of reading mirror genes. With the power of chemistry, researchers........

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