The potential for mirror bacteria to cause 'unprecedented and irreversible harm'
This short post introduces a potentially devastating hypothetical form of life assuming no background knowledge from readers.
It's split up into the following sections:
- What are Mirror Bacteria and Why are they Different?
- How Mirror Bacteria Could Cause Harm
- An Overview of the Current State of the Field
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1. What are Mirror Bacteria and Why are they Different?
To understand what mirror bacteria are, I'll first explain the relevant concepts found in normal biochemistry (what is currently found in nature). To do this, we need to understand the terms chirality and left/right handedness.
Chirality is a property of an object that cannot be superimposed on its mirror image, even if you rotate it. An example of an object that is chiral is your hand since there's no way you can place one hand over the other (its mirror image) such that they perfectly match.
Now imagine a molecule that is chiral. Call the molecule 'A' and its mirror-image form 'B'. By convention, scientists define one of the two mirror forms (for example A) as 'left-handed' and the other (here B) as 'right-handed' (often labelled using L/D or R/S notation). The choice of this convention was historically arbitrary, so don't worry about understanding why a particular molecule is left- or right-handed (it's simply to differentiate between the mirror forms).
It so happens that life is built from chiral molecules and that the biology found on Earth strongly 'prefers' one handedness over the other. What I mean specifically is that living systems are strongly biased toward one enantiomer (each of a pair of molecules that are mirror images of each other) in their core biomolecules, rather than using both equally. For example, proteins are built almost exclusively from L-amino acids, while the sugar backbones of DNA and RNA use D-sugars (D-deoxyribose and D-ribose).
Now, imagine a mirror biological system that would have the opposite chirality (from our current system) at every level. All molecules would be replaced by their mirror versions; e.g. amino acids would be almost exclusively right-handed.
Mirror bacteria would be biochemically incompatible with current organisms. For instance,
- they likely wouldn't be affected by many existing antibiotics
- they likely wouldn't be digestible by most organisms
- our enzymes could not break down their molecules
- they could not digest many of our chiral food sources (by symmetry)
As far as we know, mirror bacteria do not exist in nature. However, in principle, they could be artificially created.
2. How Mirror Bacteria Could Cause Harm
If artificially created and introduced into biological systems, mirror bacteria could pose existential risks. I provide a step-by-step concrete scenario:
Intelligent bad-actors, enabled by advanced AI tools, attempt to cause mass harm by designing mirror pathogen-like bacteria that could harm humans through non-stereospecific mechanisms (i.e., mechanisms not relying on chiral receptor binding).
They release these mirror bacteria into public high-density spaces such as airports so that they spread as quickly as possible.
Due to the opposite chirality, in principle, our immune systems could be slower to respond, as much of innate immunity depends on recognizing specific molecular shapes. It would enter and spread through much of the population maybe before anyone even realises.
High bacterial growth can cause: inflammation, mechanical tissue damage, production of gases or reactive metabolites that damage cells, and acids that alter local pH.
Treatment would be much harder, since mirror bacteria would use mirror enzymes, potentially rendering many existing drugs futile.
We're too late to respond leading to catastrophic global outcomes.
Of course, a lot has to conveniently (inconveniently) go wrong for that particular scenario to occur. The point is that we do not know how to reliably control or eliminate such mirror life, and therefore might be unable to counteract the threats it could pose.
3. An Overview of the Current State of the Field
At the moment, scientists can create some complex mirror-image biomolecules. However, a full mirror organism has not been synthesized. The reason mirror biomolecule research is being done is its potential benefits for understanding origin-of-life science, astrobiology, and medical and drug development. The timelines for synthesizing a full mirror organism are generally estimated to be at least a decade away, given current (~2026) technological and scientific trends.
38 scientists, including a Nobel prize winner, have warned that building mirror life is too risky.
Think tanks such as Carnegie Endowment for International Peace are arguing for anticipatory governance and policy to prevent such life from being created.
Workshops and debates on ethics, risk mitigation, and policy frameworks are being hosted by organisations such as the Mirror Biology Dialogues Foundation (MBDF).
It is being suggested that research funders should pledge not to support mirror-bacteria creation research specifically, while allowing other mirror biomolecule work to continue.
Humanity may be capable of creating a form of life fundamentally incompatible with the ecosystem that sustains us. Whether we should matters just as much as whether we can.