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In theory, all biological structures, functions and even organisms could be recreated in their mirror image, leading to endless possibilities.Credit: Getty<\/p>\n
This week, experts in synthetic biology and microbiology, among other fields, are gathering in Manchester, UK, to explore the benefits and risks of building synthetic life<\/a>. One of the topics that will be discussed is how research might be restricted to prevent the creation of organisms made of components that are the mirror image of those that make up life on Earth. Days after the Manchester meeting, the issue will be examined at a workshop organized by the US National Academies of Sciences, Engineering, and Medicine<\/a>. And other meetings are planned<\/a>.<\/p>\n How should \u2018mirror life\u2019 research be restricted? Debate heats up<\/p>\n <\/a><\/p>\n Most of the biological molecules known to make up life on Earth have a specific handedness, or chirality. Amino acids have left-handed chirality, for example, whereas DNA is right-handed. Because mirror-image bacteria or other synthetic life forms would be made of molecules of opposite handedness (so with right-handed amino acids and left-handed DNA), the concern is that such organisms might represent a hazard to known life1<\/a>\u20133<\/a> (see also go.nature.com\/3hshyst<\/a> and go.nature.com\/3vwuytw<\/a>). For example, some of them might be capable of evading immune systems, confounding medicines, resisting predation and causing harms to humans, non-human animals, plants and ecosystems2<\/a>,3<\/a>.<\/p>\n Prohibiting the creation of molecules or biological entities of either chirality that could endanger human health or environmental stability should be uncontroversial. And discussions early in the development of a field \u2014 as well as efforts to engage the public \u2014 can be constructive when it comes to ensuring that research is conducted responsibly and ethically.<\/p>\n But in the face of vast unknowns, the noble path of pre-emptively protecting humanity from potential risks in the distant future can be slippery. And we should tread cautiously.<\/p>\n The concept of a mirror-image biological world is not new. It was first proposed in 1860 by French chemist and microbiologist Louis Pasteur4<\/a>. And the potential benefits and risks of mirror-image organisms have been discussed by the research community for more than 30 years1<\/a>\u20133<\/a> (see also go.nature.com\/3hshyst<\/a> and go.nature.com\/3vwuytw<\/a>). However, in the past few months, the conversation has abruptly shifted to calls for hard limits on basic research and funding<\/a>2<\/a>.<\/p>\n At this point, there are divergent views<\/a> (see go.nature.com\/46tgjvf<\/a> and eLetters by R. Derda et al. and D. Perrin in ref. 2) on how soon it might be possible to create mirror-image organisms; the potential benefits and risks of generating mirror-image life and of developing precursor technologies; whether moratoria on research should be imposed; and, if so, what areas of study should be restricted.<\/p>\n Given the countless unanswered questions, careful consideration of the scientific facts learnt so far \u2014 regarding what it would take to create a mirror-image life form, and the pros and cons of research on mirror-image molecular biology more broadly \u2014 is crucial for bridging divergent views and fostering rational and informed debate.<\/p>\n On the distant horizon<\/p>\n In December 2024, nearly 40 experts, including in synthetic biology, ecology and immunology, co-authored a Policy Forum article in Science2<\/a> and released a separate 299-page technical report3<\/a>. In both, the authors argued that were mirror-image life created, it would be very likely to present unprecedented risks to humans, animals, plants and ecosystems.<\/p>\n Multiple meetings have followed the Science publication, including in the United Kingdom<\/a>, the United States<\/a>, France<\/a> and the Netherlands<\/a>.<\/p>\n But how close are scientists to being able to create a mirror-image life form?<\/p>\n Scientists have been pondering the idea of a mirror-image world of biology for more than a century.Credit: Jorg Greuel\/Getty<\/p>\n Dozens of research groups, including those at pharmaceutical companies, have been synthesizing and investigating mirror-image proteins, DNA and RNA for the past three decades to understand fundamental biology and develop therapeutics5<\/a>\u201314<\/a>. My colleagues and I have been exploring various mirror-image molecular processes, too. These include the replication of mirror-image DNA, the transcription of mirror-image DNA into mirror-image RNA and the translation of mirror-image RNA into mirror-image proteins \u2014 in other words, a mirror-image version of the central dogma of molecular biology7<\/a>\u201311<\/a>.<\/p>\n Research in mirror-image molecular biology is still in its infancy. But scientists working in this field have been humbled by the tremendous challenges of exploring this unknown world5<\/a>\u201314<\/a>. The creation of mirror-image organisms, if it ever became feasible, would face monumental conceptual and technical barriers.<\/p>\n Hundreds to thousands of cellular components \u2014 including proteins, nucleic acids, membranes, metabolites and complex carbohydrates called glycans \u2014 would need to be synthesized chemically or enzymatically in their chirally inverted forms. Some of these are encoded directly by DNA. But many are synthesized or modified by other complex biological machinery, meaning their compositions and structures cannot simply be derived from DNA sequences. And many have not yet been characterized.<\/p>\n It took our group nearly four years to chemically synthesize a mirror-image protein fragment of up to around 470 amino acids9<\/a> \u2014 the longest single-chain mirror-image polypeptide reported so far. Synthesizing longer polypeptides and membrane proteins that are rich in water-repelling (hydrophobic) domains would be even harder.<\/p>\n Asilomar conference took courage and foresight \u2014 today, inclusivity would also be crucial<\/p>\n <\/a><\/p>\n Likewise, we have been trying to chemically synthesize a highly simplified version of a mirror-image ribosome since 2016, and are still years away from achieving it. Should we succeed, this ribosome will lack protein and RNA modifications and will not have aminoacyl-tRNA synthetases (the enzymes responsible for attaching specific amino acids to their corresponding transfer RNAs during protein biosynthesis)8<\/a>,11<\/a>. This means it will be able to produce only short peptides and small proteins (say, of about 300 amino acids)8<\/a>.<\/p>\n Even if all the constituent molecules of the simplest bacterium could be synthesized in their mirror-image forms, these would need to be folded correctly and assembled with spatio-temporal precision to create a mirror-image bacterium that functions as a complex, autonomously replicating cell.<\/p>\n Many laboratories have built non-living membrane-bound compartments, in which copies of DNA and RNA molecules can be made or in which RNA molecules can be translated into proteins. Although researchers have been able to isolate biologically derived ribosomes and other cellular machinery with natural chirality for decades, no lab has been able to use this machinery to produce all the essential cellular components in vitro.<\/p>\n Researchers don\u2019t yet know how to assemble a natural-chirality self-replicating cell from biologically derived building blocks \u2014 let alone how to chemically synthesize a mirror-image one from the ground up. And although other strategies for the creation of mirror-image life have been proposed (such as the stepwise conversion of a natural-chirality cell into a mirror-image cell2<\/a>,3<\/a>), there is insufficient evidence to support their feasibility.<\/p>\n In short, it is crucial to distinguish mirror-image molecular biology from the creation of mirror-image organisms. A self-replicating cell has molecular diversity, metabolic complexity and structural intricacy that are orders of magnitude greater than what\u2019s found in any currently synthesizable biomolecular system. And the creation of a mirror-image organism lies well beyond the reach of present-day science.<\/p>\n Endless possibilities<\/p>\n Because all biological structures, functions and even organisms could be recreated in their mirror image, the possibilities \u2014 good and bad \u2014 in a looking-glass world are endless. As well as considering the risks of hypothetical scenarios, such as the creation of mirror-image life, it is important to keep in mind the realized and potential benefits of the mirror-image molecular biology research that is already under way5<\/a>\u201314<\/a>.<\/p>\n When given to animals or humans, mirror-image peptides and nucleic-acid drugs can trigger a much milder immune response compared with their natural-chirality counterparts13<\/a>. They are also more resistant to biodegradation, which means a dose can stay in the body for much longer. The implications for drug discovery are profound.<\/p>\n Mirror-image enzyme copies looking-glass DNA<\/p>\n <\/a><\/p>\n Dozens of mirror-image peptides, DNA and RNA molecules are already being developed as drug candidates for cancer, metabolic diseases, infectious diseases and inflammatory disorders10<\/a>,13<\/a>. Indeed, a synthesized mirror-image ribosome would probably drastically accelerate pharmaceutical discovery by enabling the high-throughput production of mirror-image peptides8<\/a>,11<\/a>.<\/p>\n All sorts of other possible applications of mirror-image molecules or biological entities can be imagined, particularly in medicine and sustainability.<\/p>\n Mirror-image glucose tastes as sweet as its natural-chirality counterpart, but does not provide calories because it is not metabolized by the enzymes found in natural-chirality organisms15<\/a>. This means that mirror-image glucose and other mirror-image sugars could serve as non-caloric sweeteners or other food additives.<\/p>\n Mirror-image DNA molecules have the same capacity to hold information as their natural-chirality counterparts do, but they are more resistant to biodegradation and easier to distinguish from contaminant (natural-chirality) DNA. As such, mirror-image DNA molecules can serve as robust information repositories9<\/a>.<\/p>\n Nanoparticles or nanocapsules, built using mirror-image proteins, could enable the safe delivery of drugs by shielding them from the immune system. Mirror-image DNA or RNA molecules designed to detect the presence of certain human proteins and metabolites, such as thrombin10<\/a> and guanine11<\/a>, could be used as diagnostic biosensors in clinical settings.<\/p>\n Meanwhile, mirror-image versions of enzymes that are capable of degrading plastics that have no chirality could offer a solution to plastic pollution12<\/a>. Like their natural-chirality counterparts, such enzymes can break down plastics but are more resistant to biodegradation themselves. In principle, mirror-image versions of enzymes that can capture carbon might similarly be used to help address climate change.<\/p>\n Plastic-consuming bacteria, shown in this artist\u2019s impression, contain enzymes that degrade plastics. Biostable mirror-image versions of these proteins could offer a solution to plastic pollution.Credit: Thomas Parsons\/Science Photo Library<\/p>\n As well as providing solutions for all sorts of practical problems, basic research on biology through the looking glass could offer insights into the structures and functions of biomolecules. It could shed light on the origin of homochirality (the dominance of one set of chiral molecules in known forms of life), and even on the origin of life11<\/a>. It could guide searches for new life forms, for instance, on Earth as well as on other planets.<\/p>\n Of course, the very properties that promise to make mirror-image proteins and nucleic acids so useful in so many contexts \u2014 their biostability and tendency to induce only a mild immune response in humans and other organisms \u2014 could also make certain mirror-image organisms harmful1<\/a>\u20133<\/a> (see also go.nature.com\/3hshyst<\/a> and go.nature.com\/3vwuytw<\/a>).<\/p>\n","protected":false},"excerpt":{"rendered":"In theory, all biological structures, functions and even organisms could be recreated in their mirror image, leading to…\n","protected":false},"author":2,"featured_media":140899,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[59,4230,4231,65496,90,8360,16710,7923,56,54,55],"class_list":{"0":"post-140898","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-gb","9":"tag-humanities-and-social-sciences","10":"tag-multidisciplinary","11":"tag-research-management","12":"tag-science","13":"tag-scientific-community","14":"tag-synthetic-biology","15":"tag-therapeutics","16":"tag-uk","17":"tag-united-kingdom","18":"tag-unitedkingdom"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/140898","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=140898"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/140898\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/140899"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=140898"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=140898"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=140898"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/www.newsbeep.com\/uk\/wp-content\/uploads\/2025\/09\/d41586-025-02912-0_51450684.jpg\"\/)
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