What Are “Mirror Bacteria” And Are They A Threat To Humanity?

What are “mirror bacteria”?

To understand mirror bacteria, we first need to take a look at one of the key properties of the molecules of life as we know them; they have homochirality, or uniformity of “handedness”. This means that they only come in one particular form that cannot be superposed onto its mirror image. 

You can visualize this property using a pair of gloves. Place them out in front of you so that they’re mirroring each other, then put the right one on top of the left. Try rotating it – no matter what you do, they’ll never line up perfectly.

High school biology teachers will likely have told you that DNA is exclusively “right-handed”, while nearly all amino acids are left-handed. The processes in our cells and those of other organisms rely on these conformations, and they can govern how organisms interact with each other too.

In mirror bacteria, however, the molecules of life are – as you might’ve guessed from the name – mirrored. At least, theoretically; no one’s actually made any mirror lifeforms yet.

Nonetheless, with a hefty chunk of money and some pretty big scientific advances, it remains a possibility, albeit one that the aforementioned experts believe is at least a decade away. 

But given that the creation of mirror bacteria would be a “radical departure” from what we know about life, it’s well worth investigating what the potential risks of mirror bacteria may be before they arrive.

Are mirror bacteria a risk to us?

The expert group – which includes a number of Nobel laureates, famed geneticists, and those trying to de-extinct the woolly mammoth – doesn’t mince its words.

“Although we were initially skeptical that mirror bacteria could pose major risks, we have become deeply concerned […] our view is that mirror bacteria and other mirror organisms should not be created,” they write in a policy forum that summarizes the findings of their report.

One of the primary reasons for this is because of the potential implications for the spread of disease. The researchers point to the fact that immune systems are mediated by chiral molecules – theoretically, this means that mirror bacteria are likely to be able to go under the radar, “potentially causing lethal infection in humans, animals, and plants.”

It could also mean that they are capable of avoiding bacteria’s natural predators, bacteriophages, too, as well as human-made controls like antibiotics.

That’s not to say that such scenarios will become a reality if mirror bacteria are created, nor will they become a reality overnight. As one member of the group, professor of biochemistry Michael Kay explained in a statement, “[T]here's a lot of uncertainty in this determination. At this point, we don't have enough information to make a definitive estimate of what the risk would be.”

Equally, that doesn’t mean that those risks shouldn’t be evaluated, and the authors actively encourage further research to be conducted into the matter – while also recommending that research with the goal of creating mirror bacteria be prohibited.

“Once a mirror cell is made, it's going to be incredibly difficult to try to put that genie back in the bottle,” said Kay.

The technical report is published in the Stanford Digital Repository and an overview of the findings is published in Science.