Research and analysis

Mirror life

Published 12 June 2025

Rapid projects support government departments to understand the scientific evidence underpinning a policy issue or area by convening academic, industry and government experts at a single roundtable. These summary meeting notes seek to provide accessible science advice for policymakers. They represent the combined views of roundtable participants at the time of the discussion and are not statements of government policy.

What are the main risks and opportunities associated with researching and developing ‘mirror life’, including along the pathway of development from cell components to self-replicating cells?

Meeting notes from roundtable chaired by Professor Dame Angela McLean, Government Chief Scientific Adviser, facilitated by the Government Office for Science.

22 January 2025

Key points

• A clear distinction should be made between research to develop mirror components (individual molecules such as peptides and enzymes) and mirror organisms or cells (or any biological unit capable of self-replication), even though both are sometimes termed ‘mirror life’.  

• This distinction has important implications for regulating research without restricting innovation; beneficial scientific and technological advances for therapeutics and novel materials, for example, could cease if all mirror life research was entirely banned. 

• There are distinct challenges associated with development of all mirror components. There also remain very substantial challenges around the creation of synthetic, non-mirrored cells. Overcoming these challenges will be required for the creation of mirror life.  

• While there is some consensus that mirror organisms or cells are at least decades away from realisation, fundamental breakthroughs – which could accelerate progress – cannot be ruled out.

Definitions and feasibility of developing ‘mirror life’

1. Chiral molecules are molecules that cannot be superimposed on their mirror image by any rotation or translation. Mirror molecules are chiral molecules that are the mirror image of their natural forms and can include proteins, nucleic acids, sugars and lipids.

2. Mismatched chirality may prevent interactions between natural organisms and mirror molecules. For example, an antigen on the surface of a mirror bacteria would not be recognised by receptors on host immune cells and would not incite an immune response.1 

3. The unique properties of component mirror molecules (‘component’ covers a diversity of molecules that comprise a natural cell) could have a number of practical applications, spanning agriculture, medicine and manufacturing (see below). 

4. While some small mirror components already exist, a sequence of developments is needed to create mirror life (an organism composed entirely of mirrored chiral molecules that does not occur in nature); this would be extremely difficult if even possible. 

5. Creation of a synthetic cell is also a pre-requisite for creating mirror life. Producing synthetic cells (non-mirrored) is a significant area of research (Rohden et al., 2021; Dogterom et al., 2024) and a focus of research grants internationally.

6. The fundamental processes of how life is formed, including how to progress from biological molecules to a fully functioning and self-replicating cell, are not understood. Cells took billions of years to evolve naturally, and there may be intermediary stages that we cannot foresee or design, as of yet. There are huge challenges to overcoming these unknowns in both natural and mirror life.

Therapeutic benefits of mirror life components

7. One motivation for developing mirror components is that opposite chirality biomolecules are more likely to be invisible to immune systems and less susceptible to enzymatic breakdown within host organisms, giving them increased stability and longer half-lives. 

8. Mirror components could be put to therapeutic uses in humans, animals and plants. Given their increased stability, mirror peptides (for example) are often more effective against their targets while less damaging to host cells and less likely to be rejected by these cells (Shi et al., 2022). 

9. Antimicrobial peptides (AMPs) are produced by host organisms to fight bacteria. There is an opportunity (currently being researched; Lander et al., 2022) to use mirror AMPs to slow the evolution of antibiotic resistance (Lazzaro et al., 2020; Jangir et al., 2023).  

10. Similarly, there are opportunities from developing mirror aptamers (short sections of single stranded DNA or RNA) (Chen et al., 2022) that exert a binding function and hence a biological (and potentially therapeutic) effect. 

11. Producing some mirror components with strong therapeutic potential at scale is not currently possible using synthetic chemistry. A mirror organism could be created as a production host for mirror peptides and enzymes, for example – but this is both challenging (see above) and high risk (see below) (Xu & Zhu, 2022). Scaleable production of useful mirror molecules represents a key motivation for developing mirror organisms. 

12. Restrictions on the development of mirror components could have a negative effect on legitimate therapeutic research. Regulations should be carefully considered, e.g. by setting limits on mirror DNA size, to prevent creation of a self-replicating mirror genome while still allowing research into useful mirror molecules consisting of smaller DNA strands, such as aptamers.

Other potentially beneficial applications of mirror life components

13. Biological and non-biological materials with opposite chirality can have a variety of useful applications for sustainable materials science. These include their different interactions with light for photonics (Zhong et al., 2024), improved tensile strength and stability, biofilm applications (Wang et al., 2024) and different magnetic and conductive properties (Bloom et al., 2024). 

14. The stability of mirror DNA can be exploited for DNA data storage, potentially providing a more durable medium (Fan et al., 2021). Regulations affecting synthesis of long mirror-DNA sequences would impact this area of research.

Risks of developing self-replicating mirror cells

15. While there are legitimate applications of mirror life components, research into mirror organisms – though largely driven by scientific curiosity – carries clear risks. 

16. With opposite chirality, a mirror bacterium, for example, may evade natural immune systems, but chiral mismatch may also prevent the bacterium from pathogenic effects including (for intra-cellular bacteria) the invasion of host cells. The balance between immune evasion and reduced pathogenicity is not known, meaning there are significant uncertainties around how mirror bacteria could behave in hosts. 

17. There is also the potential for mirror bacteria to act like cancer: taking up oxygen, nutrients and physical space within a host. While there are uncertainties around how effectively mirror bacteria might grow within a host given the opposite chirality of available nutrients, some substrates in the body contain achiral nutrients. Even a small amount of bacterial growth could prove harmful, and mirror bacteria might evolve to use nutrients of opposite chirality.  

18. Photosynthetic mirror life arguably poses the most significant threat, as this could sustain itself without an external food source. 

19. The feasibility of mirror viruses is less certain than for mirror bacteria. While bacteria can independently self-replicate, viruses are can only reproduce using the machinery of infected cells. A mirror virus would be unable to interact with a host’s cell machinery given mismatched chirality.  

20. A lack of natural predation and a lack of immune response to mirror organisms could mean that they could out-compete other life forms for resources, with implications for water, food supply, biodiversity and ecosystem stability.

Detection and mitigation of risks

21. It is important to understand the potential spillover impacts of mirror research for other fields to inform both research funding and regulatory thinking. 

22. Some careful thought should be spent on what it would mean to be prepared to encounter mirror life, including potential mitigations and countermeasures. However, that effort should be proportionate to the long timescales and current low likelihood of the development of full self-replicating mirror organisms. 

23. We won’t understand many risks associated with mirror life unless it comes into being.  

24. Current biosurveillance methods to detect threats to health would not be able to detect mirror life because they only recognise natural chirality. 

25. There are ways to eliminate ‘escaped’ mirror life if it was to cause infection, such as by using some current antibiotics.  

26. Countermeasures can only work to the extent that they can be deployed; it would not be possible to use antibiotics on entire ecosystems that mirror bacteria might colonise.  

27. ‘Safety switches’ or identification ‘barcodes’ could be incorporated into synthesised cells to mitigate the risk of uncontrolled release. However, malicious actors or natural evolution could possibly adapt cells to overcome such mitigations.  

28. There should be a coalition among funders, researchers, governments and civil society to develop appropriate guidelines to manage the development of mirror molecules and prevent the development of replicating mirror organisms.  

29. There should be collective international agreement to monitor research into self-replicating mirror cells and to develop appropriate mitigations on a case-by-case basis. Any such agreement could, of course, be ignored by bad actors. 

30. Stopping all research into mirror life would compromise the UK’s ability to manage risks and benefit from opportunities.

Participants

• Angela McLean (GCSA, chair)
• Anna Peacock (University of Birmingham)
• Craig MacLean (University of Oxford)
• Greg Winter (University of Cambridge)
• Patrick Yizhi Cai (University of Manchester)
• Paul-Enguerrand Fady (Centre for Long-Term Resilience)
• Paul Freemont (Imperial College London)
• Paul McGonigal (University of York)
• Ross Anderson (University of Bristol)
• Sana Zakaria (RAND Europe)
• Thomas Gorochowski (University of Bristol)
• Wendy Barclay (Imperial College London)

References

Bloom, B.P., Yossi Paltiel, Naaman, R. and Waldeck, D.H. (2024). Chiral Induced Spin Selectivity. Chemical reviews, 124(4), pp.1950–1991. doi:https://doi.org/10.1021/acs.chemrev.3c00661.  

Chen, J., Chen, M. and Zhu, T.F. (2022). Directed evolution and selection of biostable l-DNA aptamers with a mirror-image DNA polymerase. Nature Biotechnology, 40(11), pp.1601–1609. doi:https://doi.org/10.1038/s41587-022-01337-8.  

Dogterom, M., Kamat, N.P., Jewett, M.C. and Adamala, K.P. (2024). Progress in Engineering Synthetic Cells and Cell-Free Systems. ACS Synthetic Biology, 13(3), pp.695–696. doi:https://doi.org/10.1021/acssynbio.4c00100.  

Fan, C., Deng, Q. and Zhu, T.F. (2021). Bioorthogonal information storage in l-DNA with a high-fidelity mirror-image Pfu DNA polymerase. Nature Biotechnology. doi:https://doi.org/10.1038/s41587-021-00969-6.  

Jangir, P.K., Ogunlana, L., Szili, P., Czikkely, M., Shaw, L.P., Stevens, E.J., Yang, Y., Yang, Q., Wang, Y., Pál, C., Walsh, T.R. and MacLean, C.R. (2023). The evolution of colistin resistance increases bacterial resistance to host antimicrobial peptides and virulence. eLife, [online] 12, p.e84395. doi:https://doi.org/10.7554/eLife.84395.  

Lander, A.J., Jin, Y. and Luk, L.Y.P. (2022). D‐Peptide and D‐Protein Technology: Recent Advances, Challenges, and Opportunities**. ChemBioChem, 24(4). doi:https://doi.org/10.1002/cbic.202200537.  

Lazzaro, B.P., Zasloff, M. and Rolff, J. (2020). Antimicrobial peptides: Application informed by evolution. Science, [online] 368(6490). doi:https://doi.org/10.1126/science.aau5480.  

Rohden, F., Hoheisel, J.D. and Wieden, H.-J. (2021). Through the looking glass: milestones on the road towards mirroring life. Trends in Biochemical Sciences, 46(11), pp.931–943. doi:https://doi.org/10.1016/j.tibs.2021.06.006. 

Shi, Y., Hussain, Z. and Zhao, Y. (2022). Promising Application of D-Amino Acids toward Clinical Therapy. International Journal of Molecular Sciences, 23(18), pp.10794–10794. doi:https://doi.org/10.3390/ijms231810794. 

Wang, Y., Zhang, X., Xie, D., Chen, C., Huang, Z. and Li, Z.A. (2024). Chiral Engineered Biomaterials: New Frontiers in Cellular Fate Regulation for Regenerative Medicine. Advanced Functional Materials. doi:https://doi.org/10.1002/adfm.202419610.  

Xu, Y. and Zhu, T.F. (2022). Mirror-image T7 transcription of chirally inverted ribosomal and functional RNAs. Science, 378(6618), pp.405–412. doihttps://doi.org/10.1126/science.abm0646. 

Zhong, X., Yuan, L., Liao, X., Hu, J., Xing, S., Song, S., Xi, J. and Zheng, Y. (2024). Circularly Polarized Organic Light‐Emitting Diodes Based on Chiral Hole Transport Enantiomers. Advanced Materials, 36(18). doi:https://doi.org/10.1002/adma.202311857.