The study, published in Nature Communications, focuses on biomolecular condensates: concentrated, membrane-free compartments formed when molecules separate from their surroundings in a process known as liquid-liquid phase separation. Unlike conventional organelles, condensates do not require a surrounding lipid membrane. Instead, weak and reversible interactions among molecules cause them to cluster into droplets, much like oil separating from water. In modern cells, comparable condensates help organize processes such as gene regulation, RNA processing and cellular stress responses. Under prebiotic conditions, RNA droplets could have concentrated otherwise dilute molecules, increasing the chances that RNA strands would interact, copy information or participate in chemical reactions. They may also have reduced exposure to damaging environmental conditions, including heat, acidity and fluctuating concentrations of salts and minerals.

The new work builds on earlier research from the Banerjee laboratory showing that RNA can assemble into liquid-like droplets at elevated temperatures. In the latest experiments, the team compared RNA with single-stranded DNA molecules designed to contain essentially the same sequences. The comparison allowed the researchers to isolate the influence of chemical structure rather than differences in genetic information. RNA began forming condensates at temperatures approximately 10 degrees Celsius lower than the corresponding DNA. That result indicates that RNA has a stronger intrinsic tendency to condense as temperature rises. The researchers also observed an important difference in the internal organization of the droplets. RNA was more likely than DNA to form interconnected molecular networks, causing the condensates to shift from relatively fluid materials toward more elastic, gel-like states.

The contrast between the two nucleic acids is striking because RNA and DNA are chemically similar. Both are built from repeating nucleotide units, each containing a sugar, a phosphate group and a nitrogen-containing base. The critical distinction lies in the sugar. RNA contains ribose, whose 2′ carbon carries a hydroxyl group made of oxygen and hydrogen. DNA contains deoxyribose, which lacks that oxygen-containing 2′-hydroxyl, or 2′-OH, group. This apparently modest change alters how the nucleic-acid backbone interacts with its surroundings. According to the study, the 2′-OH helps RNA interact more strongly with magnesium ions and changes the hydration shell surrounding the molecule. RNA retains fewer water molecules around its backbone than the comparable DNA, making RNA strands more likely to approach one another and participate in the interactions needed for condensation.

Magnesium appears to be especially important because positively charged ions can partially offset the negative charges carried by the phosphate groups in RNA and DNA. Without this charge screening, neighboring nucleic-acid strands repel one another strongly. Magnesium reduces that electrostatic barrier, allowing the polymers to come closer. The researchers’ temperature-controlled microscopy experiments showed how these molecular interactions changed as the samples were heated. They supplemented the imaging with small-angle X-ray scattering, a technique that reveals the nanoscale arrangement of molecules, and molecular-dynamics simulations carried out by collaborators at Princeton University. Together, the approaches linked the visible emergence of droplets to changes in hydration, ion coordination and the organization of RNA chains at microscopic scales.

The researchers then performed a chemical test of the proposed mechanism by modifying the 2′-OH group. They replaced it with a 2′-O-methyl group, a modification found in many naturally occurring RNA molecules and widely used to alter RNA stability and behavior. The modified RNA showed a weaker tendency to condense, and its resulting materials displayed different physical properties. In particular, changing the group affected whether the condensates remained dynamic and fluid or developed interconnected, gel-like structures. The experiment strengthened the conclusion that the 2′-OH is not merely a passive chemical feature. It actively influences how RNA molecules bind ions, organize water and establish the network of contacts that governs a condensate’s transition from a droplet to a more arrested material.

That transition could have mattered during the origin of life. A liquid condensate can continuously exchange molecules with its surroundings, allowing reactions and molecular rearrangements to proceed. A gel-like network, by contrast, can hold RNA strands in place for longer periods and may provide greater physical protection. The two states could therefore offer different advantages: fluid droplets might support rapid interactions and chemical activity, while more rigid networks could preserve vulnerable molecules during environmental stress. The researchers are not claiming that modern RNA droplets were themselves the first cells, nor that condensates alone solve every problem posed by the RNA world. Instead, the findings suggest that RNA possessed chemical properties capable of producing organized compartments without membranes, potentially creating intermediate environments between freely dispersed molecules and fully developed cellular life.

The Banerjee laboratory is now investigating whether RNA condensates can be engineered to carry out basic cell-like functions, including biochemical reactions. The long-term goal is to create active, dynamic, cell-sized compartments made primarily or entirely from RNA. Such systems could help scientists explore how molecular networks became organized before biological membranes, proteins and complex genomes emerged. They may also contribute to the design of synthetic cells and programmable biomolecular materials. The study’s central message is that large-scale biological organization can arise from a very small molecular distinction. One hydroxyl group can alter ion binding, water structure, phase separation and the mechanical state of an entire condensate. If similar RNA compartments existed on the early Earth, their ability to concentrate, protect and organize molecules may have helped bridge the enormous gap between chemistry and the first cellular systems.

Subject of Research: RNA condensates, phase separation, and the molecular origins of cellular organization

Article Title: The role of the 2’-OH group in phase separation and percolation transitions of RNA

News Publication Date: 31 July 2026

Web References: https://www.nature.com/articles/s41467-026-75961-2

References: Nature Communications; DOI: 10.1038/s41467-026-75961-2

Image Credits: Priya Banerjee/University at Buffalo

Keywords

RNA condensates, RNA droplets, DNA, 2′-hydroxyl group, phase separation, liquid-liquid phase separation, RNA world hypothesis, origin of life, biomolecular condensates, magnesium ions, molecular dynamics, synthetic cells, prebiotic chemistry, gel-like networks

For decades, the enigma of how RNA molecules could self-replicate and evolve under prebiotic conditions has captivated researchers. The RNA world hypothesis posits that RNA not only carried genetic information but also exhibited catalytic activities before proteins emerged. However, creating a sustainable system for RNA replication in the laboratory, especially one that is open-ended and exponential, has remained a monumental challenge. The current study by Attwater, Augustin, Curran, and colleagues represents a critical leap forward in recreating plausible prebiotic replication systems under laboratory conditions.

Central to the researchers’ methodology is the use of trinucleotide substrates—three-unit RNA building blocks—that serve as primers for the polymerase ribozyme. Unlike previous methods relying on mononucleotides, trinucleotides offer multiple advantages, including increased binding stability, improved catalytic efficiency, and more controlled elongation steps. This substrate choice mimics a potential primitive scenario where short RNA oligomers, rather than single nucleotides, could have facilitated early RNA replication events.

However, what truly sets this study apart is its innovative application of pH–freeze–thaw cycles. This process involves repeatedly subjecting the reaction mixture to fluctuating ionic conditions and temperatures that simulate natural environmental stresses, such as those found in frozen ponds or icy rock crevices on primordial Earth. These cycles induce periodic acidification and ice crystal formation, which are hypothesized to concentrate reactants, remove inhibitory side products, and promote strand separation—key factors for efficient RNA replication.

The polymerase ribozyme utilized in this study is an engineered catalytic RNA capable of template-directed RNA polymerization. Previous iterations of such ribozymes were limited by processivity and the length of RNA strands they could replicate. By integrating trinucleotide substrates and subjecting the system to freeze–thaw cycling, the researchers dramatically enhanced ribozyme activity, enabling the replication of RNA strands of significant length and complexity. This has profound implications for understanding how early RNA-based life forms might have overcome barriers to replication fidelity and speed.

Importantly, the open-ended nature of the replication observed means that RNA strands can be copied repeatedly without predetermined length limits, a prerequisite for Darwinian evolution. Exponential amplification—where replicated RNA strands serve as templates for subsequent rounds of replication—was demonstrated, marking a fundamental shift from previous linear or stalled replication systems. Such exponential behavior closely resembles the principles underlying modern nucleic acid amplification techniques like PCR but achieved here through purely ribozyme-catalyzed reactions under prebiotically plausible conditions.

The study also delves into kinetic and thermodynamic analyses to shed light on why trinucleotide substrates outperform mononucleotides in this context. Their multivalent interactions with the ribozyme’s catalytic site appear to stabilize transition states and facilitate rapid, processive synthesis. Meanwhile, the freeze–thaw environment modulates the solution pH dynamically, alternating between acidic and more neutral conditions, which apparently cycles the ribozyme between active conformations and strand release phases necessary for effective replication.

Furthermore, this research tackles one of the greatest challenges in origin-of-life chemistry—the fidelity of copying information. The trinucleotide approach inherently reduces errors by enforcing correct base-pairing interactions over a longer substrate length. Combined with the physical segregation effects induced by freezing, which likely minimize off-target or inhibitory binding, the system yields replication products with higher sequence integrity. This opens avenues for future work in early molecular evolution and the development of self-sustaining RNA-based genetic systems.

The implications of this work stretch beyond simply understanding prebiotic chemistry. The ability to harness ribozymes and trinucleotide substrates in a controlled yet biomimetic environment could inspire new biotechnological tools for RNA synthesis and manipulation. For example, enzymatic amplification methods that rely purely on RNA rather than proteins could benefit from this approach, potentially enabling applications in synthetic biology, molecular diagnostics, and therapeutic RNA production.

Critically, this finding also challenges existing dogmas about the conditions necessary for life’s emergence. It suggests that rather than requiring stable and benign environments, fluctuating environmental stresses like freeze–thaw cycles, once thought to be detrimental, may have been essential drivers enabling early molecular complexity. This counterintuitive insight prompts a reconsideration of where and how life’s essential chemical reactions could have thrived on the young Earth.

In addition to the fundamental science, the collaborative nature of the work, involving insights from chemistry, biophysics, and molecular evolution, underscores the multidisciplinary nature of modern origins-of-life research. By integrating experimental biochemistry with geochemical plausibility, the authors offer a physically realistic scenario that aligns with geological evidence. This adds credibility to the proposed mechanisms and helps bridge the gap between molecular experiments and planetary science.

Looking forward, the researchers note several exciting directions, including expanding the repertoire of trinucleotide substrates, exploring longer and more complex RNA templates, and investigating the potential for ribozymes to catalyze other primordial biochemical reactions. There is particular interest in whether such ribozyme systems can remain robust under varying conditions mimicking tidal pools, hot springs, or extraterrestrial icy moons, contexts increasingly relevant as astrobiology broadens its scope.

Moreover, the study raises enticing prospects for the engineering of synthetic life forms or protocells capable of autonomous replication and evolution. If trinucleotide-mediated ribozyme replication can be integrated with compartmentalization and metabolic processes, it would represent a major stride toward constructing minimal life-like systems from the bottom up.

In essence, the discovery that pH-modulated freeze–thaw cycles can unlock open-ended RNA replication by polymerase ribozymes using trinucleotide substrates provides a vivid glimpse into the molecular dance that may have initiated life itself. By unveiling a plausible, experimentally validated mechanism for exponential RNA amplification without protein enzymes, this research pushes the boundary of the known chemical origins of life and opens up fascinating horizons both for basic science and future technological innovation.

As the scientific community digests these findings, one thing is clear: the complexity and adaptability of RNA molecules continue to astonish and inspire. This work not only deepens our understanding of early molecular evolution but also exemplifies how seemingly harsh environmental conditions could foster the intricate biochemistry necessary for life, turning the icy grip of freeze–thaw cycles from an obstacle into an enabling force for the genesis of biological information.

Subject of Research:
Mechanisms enabling exponential RNA replication by polymerase ribozymes under prebiotically plausible conditions involving trinucleotide substrates and pH–freeze–thaw cycles.

Article Title:
Trinucleotide substrates under pH–freeze–thaw cycles enable open-ended exponential RNA replication by a polymerase ribozyme.

Article References:

Attwater, J., Augustin, T.L., Curran, J.F. et al. Trinucleotide substrates under pH–freeze–thaw cycles enable open-ended exponential RNA replication by a polymerase ribozyme. Nat. Chem. (2025). https://doi.org/10.1038/s41557-025-01830-y

Image Credits: AI Generated

The RNA world hypothesis posits that RNA molecules were the first to carry genetic information and catalyze biochemical reactions before the evolution of DNA and proteins. However, replicating RNA strands in laboratory conditions that mirror those of the prebiotic Earth has remained a formidable challenge. This difficulty largely arises because RNA strands tend to form double helices, in which complementary strands zip tightly together. These helices are extremely stable, acting like molecular Velcro that fastens the strands and inhibits the necessary separation required for replication, leaving no opportunity for copying.

Addressing this issue, the researchers developed an innovative approach using triplet RNA building blocks, or trinucleotides, which are composed of three nucleotides linked together rather than the canonical single nucleotides standard in biology today. Employing these triplets in aqueous solutions, combined with cycles of acidic pH adjustments and heat, the team was able to induce the separation of RNA duplexes effectively. The acid and heat conditions transiently disrupted the double helix, unwinding the paired strands in a manner that is chemically plausible given geothermal and diurnal cycles on the Hadean Earth.

Following this separation, the scientists neutralized and rapidly froze the solution. In the microscopic liquid pockets or veins between forming ice crystals, they observed that the triplet building blocks coated the exposed single RNA strands. This coating prevented the RNA strands from re-annealing or zipping back together, preserving them in a configuration accessible for templated replication. As the solution was thawed, the triplets aligned themselves along the template strands and facilitated the formation of new complementary RNA strands, completing a cycle of replication without enzymatic assistance.

The cyclical process of thawing and freezing, alongside repeated shifts in pH and temperature, created an environmental scenario that plausibly mimics natural conditions on early Earth, such as those found in shallow ponds or geothermal lakes. These dynamic physicochemical changes can drive non-enzymatic RNA replication by enabling strand separation and template-directed assembly in a continuous loop. Importantly, the RNA strands produced through this mechanism were sufficiently long to exert biological functions, highlighting the potential significance of this pathway in prebiotic evolution.

Dr. Philipp Holliger, who led the study at MRC LMB, emphasized the centrality of information transfer in life’s definition. He explained that life is distinguished from mere chemistry by its ability to encode, preserve, and propagate information through molecular memory in genetic polymers like RNA. For life to arise, this informational substrate must be reliably copied across generations. The new findings demonstrate a chemical system that can achieve this fundamental step under simple, plausible conditions.

Echoing this perspective, lead author Dr. James Attwater remarked on the elusive nature of the primordial replicator. Although all contemporary organisms descend from a Last Universal Common Ancestor (LUCA), which is genetically complex, the first self-replicating molecules remain concealed in deep evolutionary history. This research reinvigorates the RNA world hypothesis by providing a feasible molecular mechanism devoid of complex enzymatic machinery necessary for modern replication, an aspect vital for pre-life chemistry.

The requirement for a simple, non-enzymatic method to replicate RNA challenged the team to explore alternatives to the stringent base-pairing systems seen in extant biology. Trinucleotides, which are absent in living organisms today, emerged as ideal candidates because they can bind in a more stable yet reversible manner, promoting efficient template copying while circumventing the kinetic trapping of RNA strands. Such molecular building blocks may well represent ancestral biochemical tools utilized by early life, which has since evolved beyond them.

Another pivotal finding was the environmental specificity of this replication process. The team discovered that replicating RNA under these conditions was not viable in freezing saltwater. Salt interferes with ice formation dynamics and prevents the concentration of RNA building blocks that freezing is supposed to achieve, thereby blocking the replication mechanism. This suggests that freshwater environments in geothermal settings would have been more conducive to the chemistry of early life’s replication processes.

Similarly, although evaporation in warm conditions can concentrate RNA, the instability of RNA molecules at elevated temperatures limits their longevity and functional capacity in such settings, according to the researchers. This underscores the delicate balance of physical parameters—temperature, solute concentration, and pH—that early Earth environments must have maintained to permit RNA’s survival and replication.

The origin of life is now thought to have been orchestrated not by RNA alone but by an interplay of various molecular constituents. Peptides (short amino acid polymers), enzymes, and lipid-based compartments likely co-evolved, each contributing vital roles such as catalysis, structural scaffolding, and protection from harsh environmental fluctuations. The current study contributes a crucial piece of this complex puzzle by elucidating how the first RNA-based replication cycles could have arisen in isolation.

Building on decades of foundational research in prebiotic chemistry, teams led by researchers such as Dr. John Sutherland and Professor Matthew Powner have demonstrated plausible synthetic pathways for essential biomolecules including nucleotides, amino acids, peptides, simple lipids, and vitamin precursors under early Earth-like conditions. The present study complements these advances by showing how RNA polymers constructed from such building blocks could replicate, thereby initiating biological information flow.

In sum, this innovative study outlines a chemically credible and experimentally validated path for the non-enzymatic replication of RNA on prebiotic Earth. By harnessing triplet RNA building blocks and environmental cycling of temperature and acidity, the research reconciles a critical gap between pure chemistry and biology, offering profound insights into the molecular dawn of life. Such breakthroughs bring us closer to unraveling one of humanity’s oldest questions: how did life begin?

Subject of Research: RNA self-replication under prebiotic Earth conditions
Article Title: A plausible chemical route for RNA replication on early Earth enabled by triplet building blocks and environmental cycling
Web References: 10.1038/s41557-025-01830-y
Image Credits: Philipp Holliger, MRC Laboratory of Molecular Biology
Keywords: Origins of life, RNA replication, prebiotic chemistry, evolutionary biology, trinucleotides, molecular biology, early Earth chemistry, non-enzymatic replication, geothermal environments, laboratory simulation