Mirror Life: Good or Bad?

Recently, an article published in the journal Science has sparked global discussion over the topic of ‘mirror life’. Today, we’re looking into this topic, and why has it resulted in mixed opinions.

“Confronting risks of mirror life” - Science

On December 12th, 2024, 38 researchers co-authored an article titled “Confronting risks of mirror life” in the journal Science, focusing mainly on the potential dangers associated with creating synthetic organisms that are based on the concept of mirror-image biological molecules (a.k.a mirror life). The article also calls for caution, emphasizing on the importance of proactively regulating this area of scientific research.

What is mirror life?

Before further understanding the advantages and drawbacks of mirror life, it is crucial to grasp the concept of ‘mirror life’ itself.

A commonly-used metaphor of mirror life are your hands. If you examine your two hands carefully, you’ll find that they are biological masterpieces. Not only do opposable thumbs make it much more convenient to use tools, they generally make our actions more precise. However, they also hide a secret. If you put your hands together (palm-to-palm), you’ll find that they are mirrored images of each other. But, if you try to place them on top of one another, you’ll find that they are non-superimposable.

Mirror life is exactly that: non-superimposable mirror images. This characteristic is also known as ‘chirality’. Specific pairs of chiral molecules that are mirror images of each other are known as ‘enantiomers’. So far, all known natural organisms are known to be homochiral, meaning they prefer utilizing one of the enantiomers. Common examples are amino acids (the building blocks of life) and sugars. Almost all natural amino acids in proteins are found in their ‘left-handed’ state, while sugars that make up nucleic acids (like DNA and RNA) are common to be ‘right-handed’.

That begs the question - why does nature prefer to have a homochiral system instead of being heterochiral? Well, there are a variety of reasons this is the case.

For starters, biological selection. Use of homochiral molecules allows for more efficient biochemical processes. Enzymes (that are typically chiral) are designed to interact with specific substrates. If a racemic mixture (50-50 of both enantiomers) were present in a single living organism, 50% of the enantiomers wouldn’t be catalyzed by one kind of enzyme, so the efficiency of reactions is greatly reduced. So as time progresses, one enantiomer would have a competitive advantage, reinforcing a homochiral system.

In addition, autocatalytic reactions could happen. This refers to a process where a product of a reaction is also functionally a catalyst for the same reaction, effectively accelerating the reaction. In a hypothetical prebiotic environment, where one enantiomer could catalyze itself, it would be a positive feedback loop, and over time, this enantiomer would have a dominating advantage over the other, creating a homochiral environment.

There are also a lot of other potential factors resulting in the phenomenon we observe today. Such factors include environmental factors like circularly polarized light (CPL) and energy differences as well as minor statistical fluctuations that may result in a ‘snowball effect’ (an initial small bias growing at a great rate).

Why does it matter?

As mirror life is primarily explored within the field of synthetic biology where researchers try to build organisms that are built from mirrored components on a molecular level, it may seem quite a long-shot that this concept can influence the lives of normal people. However, it can have a few potentially useful applications, though could equally be devastating.

Advantages of mirror life

Although still restrained to research in labs, mirror life and mirror organisms can have potentially useful applications.

One of these are therapeutics. Due to their reversed nature, pharmaceuticals using mirrored molecules could be have an enhanced longevity and making them more effective in treating diseases. For example, drugs could potentially evade detection from the body’s immune system, meaning there is no chance that the immune system would reject the drug.

There are also research applications. They could serve as unique experimental platforms for studying biological processes. Using organisms that don’t interact with natural systems, researchers could investigate questions about cellular functions. It may lead to breakthroughs in understanding cellular biology.

Mirrored organisms could also help in reducing contamination utilizing the simple fact that they would not interact with natural biological systems.

Disadvantages of mirror life

As warned in the article published in Science, there are a lot of risks and dangers associated with the further research of mirror life.

One of the most notable risks is the emergence of uncontrollable and untreatable infections. If mirrored organisms were to escape the controlled environment, they could replicate and spread while simultaneously lying undetected by the immune system of both animals and humans. What used to be an advantage in creating pharmaceuticals could quickly turn into a devastating disadvantage if not regulated and used correctly.

With the former, a much bigger problem emerges: the disruption of natural ecosystems. Mirrored organisms could behave like invasive species, out-competing native species for resources and leading to ecological imbalances and maybe even extinction of local species. Such ecological consequences could be profound, maybe even effecting whole food webs.

That is why there have been calls, lead by the 38 researchers that co-authored the Science article, to establish guidelines and regulations before attempts to actually create mirrored life are made.

Conclusion

Although an emerging technology, it can have possible impacts that would no doubt resonate far and wide. In some ways, it is similar to artificial intelligence in the sense that it can both help boosting work efficiency but may also go rogue.

So it can be worth it to pay attention to developing stories on mirror life. Who knows? It could one day cure cancer and save countless lives (hopefully).

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