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Science Camp 2025: 24 high school girls immersed in science at ESPCI Paris–PSL

Manon Thillay Isnard — 2025-11-10T15:04:50Z

Holidays in white coats: 24 high school girls immerse themselves in science at ESPCI Paris–PSL

During the autumn half-term holidays, 24 high school girls from all over France swapped their school bags for white coats. Welcomed at ESPCI Paris–PSL from 20 to 25 October, they spent a week immersed in the world of research laboratories. The aim was to give them a practical introduction to the world of science and encourage them to consider studying and pursuing careers in science.

‘With this camp, we want to offer them a week of experiences, encounters and discoveries so that they realise that science belongs to them and that they can forge their own path in it,' explains Emmanuel Fort, professor at ESPCI Paris–PSL and director of the Espace des sciences Pierre-Gilles de Gennes (ESPGG), ESPCI's scientific and cultural outreach centre.

An immersion in the heart of the laboratories

Supervised by researchers and engineering students, participants alternated between lectures, practical work inspired by the school's curriculum, and scientific creativity workshops. They also visited several iconic places of learning, such as the Curie Museum and the Paris Observatory – PSL.

This was a rare opportunity to get hands-on experience, experiment and interact directly with those who conduct research on a daily basis.

‘This camp embodies the spirit of ESPCI: learning through experience, crossing disciplines and discovering science through those who do it. If this week gives them confidence, then we will have succeeded,' emphasises Vincent Croquette, Director General of the School.

Beyond the experiments and discoveries, this week was also a human adventure. Twenty-four high school girls, from different French departments as well as Canada and Turkey, shared their collective life and scientific curiosity. Some confirmed their vocation; others discovered that science could be an open, accessible and stimulating path.

A long-standing commitment to gender equality

Through the Chemistry Biology Innovation Laboratory, the school is active on the platform "Come see my work ." It offers internships to high school students who do not have a personal network enabling them to contact university staff in their search for an internship. Other initiatives are being carried out as part of the MERCASTO programme to enable high school students from Trappes (78) to visit ESPCI Paris - PSL, visit the premises and undertake internships.

ESPCI Paris – PSL also takes internal action by regularly raising awareness among teaching and research staff about gender parity and diversity issues. Last year, for example, a conference was held to help them better identify cognitive biases during recruitment. More recently, a meeting devoted to the origins and consequences of gender imbalance in science continued this collective reflection.

Press review

Esteval -A science camp at an engineering school dedicated to female secondary school students during the All Saints' Day holidays
Franceinfo - ‘It proves that we can really do it': an article highlighting the symbolic significance and impact of the internship reserved for female high school students.
France Inter (podcast ‘Sur le terrain') - An audio report that recounts the experiences of participants in the science immersion programme.
RFI - ‘A science camp at ESPCI to inspire high school girls to pursue careers in science'

[(A savoir

The science camp's budget comes from ESPGG's own resources, a grant from PSL's "ExcellencES - Action Fablabs‘ project, a grant from the PSL 'Partage des savoirs" project, and a financial contribution from ESPCI Paris - PSL. ESPGG is grateful to its partners for their contribution and thanks them for their support.)]

Researchers develop ultrasound probe capable of visualising an entire organ in 4D

Manon Thillay Isnard — 2025-10-28T14:57:00Z

Visualisation 4D de la vascularisation d'un rein entier obtenue grâce à la sonde multi-lentille développée dans cette étude. Les veines sont représentées en bleu et les artères en rouge. Les variations de couleur indiquent la vitesse du flux sanguin : plus la couleur est vive, plus le sang circule rapidement. Les plus petits vaisseaux font moins de 100 micromètres. ©Alexandre Dizeux

For the first time, a team of researchers [1] from the Institute of Physics for Medicine has succeeded in mapping the blood circulation of an entire organ in animals (heart, kidney and liver) with great precision in four dimensions: 3D + time. This new imaging technique, when applied to humans, could both improve our understanding of the circulatory system (veins, arteries, vessels and lymphatic system) and facilitate the diagnosis of certain blood circulation-related diseases. These results are published in Nature Communications.

Blood microcirculation is a complex network that transports blood to tissues and organs through tiny blood vessels. When this mechanism functions properly, cells receive the oxygen and nutrients they need to stay healthy, while metabolic waste is efficiently removed.

Any alteration to this network, whether structural or functional, can have serious clinical consequences, including heart failure, kidney failure and various chronic diseases. However, there is currently no imaging method that can visualise microcirculation and assess the integrity of the entire circulatory system, from the large arteries to the finest arterioles, at the level of the whole organ.

With this issue in mind, the research team at the Institute of Physics for Medicine has developed the first tool capable of producing such images [2]. This is a new type of ultrasound probe, developed as part of Nabil Haidour's thesis work, under the supervision of Clément Papadacci. Thanks to this technology, scientists have been able to map the vascularisation and quantify the blood flow dynamics of three essential organs – the heart, kidney and liver – in animal models of comparable size to humans, all with unprecedented image resolution.

The non-invasive device made it possible to distinguish microcirculation even in the finest vessels (less than 100 micrometres). In the case of the liver, it was possible to identify and differentiate its three blood networks (arterial, venous and portal) thanks to their haemodynamic signature.

‘The originality of these results lies in the fact that these images allow us to visualise the vessels of an entire organ at very small scales (less than 100 micrometres) – this 4D image resolution is unprecedented, as is the ability to observe an entire large organ and its flow dynamics,' explains Clément Papadacci, Inserm researcher and last author of the study.

This technology will now be tested in humans as part of a clinical trial. Developments enabling deployment in humans are being carried out with the help of ART Ultrasons biomédicaux, a technological research accelerator created by Inserm and integrated into the Institut Physique pour la médecine. ‘The probe can be connected to small portable equipment, which would allow it to be integrated into medical practice,' explains Clément Papadacci.

"Used in clinical settings, this new technology could become a major tool for better understanding vascular dynamics as a whole, from the largest vessels to the pre-capillary arterioles. It could also help advance the diagnosis of microcirculation disorders and the monitoring of treatments for small vessel diseases, which are complex to diagnose and are diagnosed by ruling out other pathologies," concludes Clément Papadacci.

YouTube video: https://www.youtube.com/shorts/HemH8qNFozQ

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Reference:
Haidour, N., Favre, H., Mateo, P. et al. Multi-lens ultrasound arrays enable large scale three-dimensional micro-vascularisation characterisation over whole organs. Nat Commun 16, 9317 (2025).
https://doi.org/10.1038/s41467-025-64911-z

Contact:
Co-author of the study: Clément Papadacci, clement.papadacci@inserm.fr
Scientific communication at ESPCI Paris - PSL: Paul Turpault, paul.turpault@espci.fr

[1] Institute of Physics for Medicine. PhysMed, ESPCI Paris - PSL / INSERM / CNRS

[2] Research carried out as part of the MicroFlowLife study (ERC starting grant).

Anke Lindner elected Fellow of the Society of Rheology

Manon Thillay Isnard — 2025-10-21T13:59:00Z

Anke Lindner, professor and researcher at the PMMH (Physics and Mechanics of Heterogeneous Media) laboratory at ESPCI Paris – Université Paris Cité, has just been elected Fellow of the Society of Rheology (SoR). This international distinction honours her outstanding contributions to understanding the behaviour of complex fluids and her commitment to the global scientific community.

A renowned experimental physicist, Anke Lindner studies the flow of suspensions, polymers and active fluids in confined geometries. She has developed innovative microfluidic approaches that allow the microscopic dynamics of particles to be observed and directly linked to the macroscopic properties of the fluid. She and her colleagues have thus been able to measure the viscosity of bacterial suspensions for the first time and show that an active fluid can become less viscous than the solvent in which it is contained.

His research on flexible fibres in flow has also made a mark in the field, revealing how microscopic deformations in these structures influence the overall rheology of the fluid. This work, at the interface between physics, mechanics and biology, paves the way for new approaches to understanding and controlling complex flows.

“For advances in the understanding of the flow of dilute complex suspensions, such as flexible fibre or active suspensions, linking microscopic particle dynamics to macroscopic rheology using innovative microfluidic approaches.” — Society of Rheology

Winner of an ERC Consolidator Grant, the Maurice Couette Prize from the French Society of Rheology, the CNRS Silver Medal and senior member of the Institut Universitaire de France, Anke Lindner is already a Fellow of the American Physical Society. Since 2025, she has been president of the European Society of Rheology, confirming her central role in the international community of complex fluid physics.

Anke Lindner's blog: https://blog.espci.fr/alindner/
SoR press release: https://www.rheology.org/sor/Fellowship/LindnerA.aspx

Event Shape the Future of Science and Society - The Future of Materials

Manon Thillay Isnard — 2025-10-16T14:08:00Z

ESPCI Paris-PSL is pleased to invite you to the first edition of the “Shape the Future of Science and Society” event, which will focus on “The Future of Materials.” This meeting is particularly aimed at researchers and industrial players involved in the field of materials.

Convinced that today's major challenges can be met at the crossroads of science and industry, ESPCI intends to make Shape the Future for Science and Society a concrete bridge between materials science research and industry players. This event is an invitation to discover the work of our laboratories, talk with our teams, and identify avenues for collaboration that will lead to innovation.

The ambition is twofold. For industry, it is a rare opportunity to learn about what is being done at the forefront of research, to find out about the progress of their work in different fields, to identify obstacles to its implementation, and to identify opportunities for collaboration. For the School, it is an opportunity to compare its progress with expectations in the field, adjust its focus, and forge lasting partnerships with the business world.

Shape the Future aims to be a catalyst event, featuring short, impactful presentations, a startup village and booths showcasing doctoral students' work, targeted meetings, themed round tables, and networking opportunities. Each participant is invited not only to observe, but also to co-create: working with our researchers to identify technological barriers, shape the industrial challenges to be addressed together, and devise concrete roadmaps.

By participating in Shape the Future, manufacturers can anticipate technological breakthroughs, acquire emerging knowledge, and engage in structural collaborations today. It is a window onto the innovations of tomorrow, shaped at the crossroads of knowledge and application, and ESPCI is determined to make it a moment where new collaborations will be born.

Programme

The Surprising Glide of Ions Trapped on Solid Surfaces

Paul Turpault d'Huve — 2025-09-11T14:54:33Z

Who hasn't rubbed a balloon on their hair only to see it stick to a wall afterward? This childhood experiment illustrates triboelectricity, a phenomenon in which simple contact or friction causes an electrical charge transfer between two materials. Although familiar in everyday life, its mechanisms are still poorly understood. Even more surprisingly, this process is not limited to solids. It can also occur when a water droplet slides on a hydrophobic surface—a unique case of “liquid triboelectrification.”

A team of researchers [1] has now shed light on this phenomenon using an unprecedented electrostatic mapping technique, capable of tracking charges left in a droplet's wake over both time and space. The results are striking: rather than remaining confined to the initial trail, these charges spread rapidly across the entire surface. Their lateral mobility is so high that it even exceeds that of ions in aqueous solution, contrary to the expected slowdown due to contact with the solid.

Simulations conducted alongside these experiments reveal that these charges correspond to hydrated ions trapped at the interface. In other words, each ion remains surrounded by a thin shell of water molecules that partially insulates it from the substrate. In this unique state, dubbed an “ionic puddle,” the ion literally glides over the surface, limited only by friction between its hydration shell and the substrate. This interfacial friction, much lower than anticipated, explains the extraordinary diffusion speed observed.

Another surprise: the propagation of charges does not depend on their density. Ions move independently of one another, without repelling each other, indicating that the process is entirely governed by interaction with the surface. Furthermore, by adjusting the water's pH, it is possible to change both the sign and magnitude of the deposited charge, confirming the direct involvement of the ionic species in the droplet.

These findings reveal a new state of matter, called the “ionic puddle,” where hydrated ions behave like nearly free particles despite being trapped on the surface. They provide fresh insight into triboelectrification between solids, which may originate from the transfer of nanometric charged water films. In the long term, understanding the dynamics of these “ionic puddles” could inspire advances in nanofluidics, ionic electronics, or even the design of energy harvesters based on droplet motion.

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Reference
Z. Benrahla, T. Saide, L. Burnaz, E. Verneuil, S. Gravelle, & J. Comtet, Giant mobility of surface-trapped ionic charges following liquid tribocharging, Proc. Natl. Acad. Sci. U.S.A. 122 (37) e2505841122, https://doi.org/10.1073/pnas.2505841122
(2025).

Contact
Paul Turpault – Scientific Communication, ESPCI Paris - PSL
Jean Comtet – Researcher, co-author of the study

[1] Researchers from the SIMM Laboratory (Soft Matter Sciences and Engineering, ESPCI Paris – PSL University, CNRS), in collaboration with a colleague from the Interdisciplinary Physics Laboratory (Université Grenoble Alpes, CNRS).

Why is it easier to cut than to tear elastomers?

Paul Turpault d'Huve — 2025-04-24T10:25:54Z

Cutting soft yet tough materials like rubber, leather, or even meat is significantly easier with a sharp blade than by tearing— even when the tear is initiated by a notch. Researchers from the SIMM laboratory [1] at ESPCI Paris – PSL have uncovered the mechanism behind this phenomenon: cutting significantly reduces deformation and molecular damage within soft materials. Their findings were recently published in Nature Communications [2].

When a soft material is subjected to force, it undergoes substantial deformation near the crack tip—a phenomenon known as blunting. This deformation leads to the rupture of numerous molecular bonds, requiring a large amount of energy to propagate a tear. In contrast, using a blade significantly reduces blunting by concentrating the deformation in a localized area, thereby limiting damage to the molecular network.

To explore this effect, the scientists used polydimethylsiloxane (PDMS), an elastomer embedded with fluorescent molecules that respond to mechanical force (mechanophores). When a chemical bond breaks, these fluorescent markers are activated, allowing precise quantification of molecular damage caused by cutting or tearing.

The results reveal that when PDMS is cut with a blade under moderate pre-stretching, the energy required to propagate the crack is significantly lower than in the case of pure tearing. Specifically, using a blade reduces by half the average number of molecular layers that break, thus lowering the total energy needed.

These findings open up practical avenues for designing materials that respond differently to cutting and tearing, tailored to the specific demands of industrial applications. Potential fields of use include medical devices, sports equipment, personal protective gear, and even the food industry—where precise cutting with minimal internal damage is crucial to maintaining product integrity.

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Contact
Scientific communication of ESPCI Paris – PSL : Paul Turpault, paul.turpault@espci.fr

Reference
Zhao, D., Cartier, A., Narita, T. et al. Why cutting is easier than tearing elastomers. Nat Commun 16, 3203 (2025). https://doi.org/10.1038/s41467-025-58483-1

[1] Matteo Ciccotti, Costantino Creton, Donghao Zhao, Alex Cartier, Tetsuharu Narita and Frederic Lechenault (ENS)

[2] Zhao, D., Cartier, A., Narita, T. et al. Why cutting is easier than tearing elastomers. Nat Commun 16, 3203 (2025). https://doi.org/10.1038/s41467-025-58483-1

Toward a New Generation of Heavy-Electron Materials Without Rare Earths

Paul Turpault d'Huve — 2025-04-16T15:26:38Z

Nicoletta Barolini for Columbia University Artist's impression of an electron moving through a heavy fermion material: due to intense electronic interactions in certain atomic orbitals, the electrons behave as if they are much more massive, which slows their movement through the material.portent comme s'ils étaient beaucoup plus massifs, ce qui ralentit leur déplacement à travers la matière. Nicoletta Barolini for Columbia University.

Heavy fermion materials, discovered around fifty years ago, are metallic compounds in which electrons behave as if they have an effective mass much greater than that of free electrons. These materials are essential for studying strongly correlated electron systems and unconventional superconductivity, with potential applications in various quantum technologies. Traditionally, creating such materials requires the use of rare earth or actinide elements, which are often scarce, radioactive, or challenging to extract. However, a research team led by Luca de' Medici from the Laboratoire de Physique et d'Étude des Matériaux (LPEM) at ESPCI Paris – PSL has proposed and successfully tested an innovative method to produce heavy fermion materials without relying on these problematic elements.

The researchers' strategy involves two key steps. First, they select a metallic compound classified as a Hund's metal, characterized by strong electronic interactions in partially filled atomic orbitals. Second, they substitute certain metallic atoms with others until the material's conduction bands are nearly half-filled with electrons. At this point, electrons in specific atomic orbitals interact strongly with each other, significantly slowing their motion and causing them to behave as "heavy." This behavior mimics that observed in traditional heavy fermion materials containing rare earths or actinides.

To demonstrate their technique, the team chose a Hund's metal composed of cesium, iron, and arsenic, and partially replaced iron atoms with chromium atoms. Resistivity, magnetic susceptibility, and thermal expansion measurements conducted by collaborators at the Karlsruhe Institute of Technology revealed increasingly pronounced heavy-electron behavior as the material was doped. These experimental results validate their approach and pave the way for creating other heavy fermion materials without using rare earth or actinide elements.

This breakthrough also represents a significant step toward designing new quantum materials that are more accessible and environmentally friendly. By eliminating dependence on problematic elements, this method could facilitate the development of technologies leveraging the unique properties of heavy fermions, including advanced electronic devices and quantum computing applications. The next steps will involve applying this strategy to a broader range of materials and exploring their potential properties for diverse technological applications.

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References :
Paradigm for Finding d-Electron Heavy Fermions: The Case of Cr-doped CsFe2As2, Matteo Crispino, Pablo Villar Arribi, Anmol Shukla, Frédéric Hardy, Amir-Abbas Haghighirad, Thomas Wolf, Rolf Heid, Michael Merz, Christoph Meingast, Tommaso Gorni, Adolfo Avella, and Luca de' Medici, Phys. Rev. Lett. 134, (2025)

Editor suggestion APS : https://physics.aps.org/articles/v18/s15

Contact:
Scientific Communication ESPCI Paris: Paul Turpault : paul.turpault@espci.fr

Underground, Fungi Organize Large-Scale Carbon Transport

Paul Turpault d'Huve — 2025-03-21T10:29:58Z

Network of mycorrhizal filaments

Mycorrhizal fungi build intricate underground networks to exchange nutrients with plants and store carbon in the soil. Published in Nature on February 26, 2025, a study conducted by 28 researchers from around the world, including scientists from the Physique et Mécanique des Milieux Hétérogènes (PMMH) Laboratory at ESPCI Paris - PSL, reveals how these networks function as sophisticated supply chains, forming one of the most widespread symbiotic partnership in nature, forming in the roots of around 70% of plant species on Earth.

Mycorrhizal fungi rely on carbon provided by the host plant with which they form a symbiotic relationship. By colonizing plant roots, they receive the carbon necessary for their development in exchange for nutrients that support plant growth. This partnership requires managing significant constraints: balancing the construction costs of the mycorrhizal network as it expands while ensuring the efficient transport of resources over long distances toward and away from host roots.

For the first time, researchers visualized and quantified the growth of mycorrhizal networks using a specially designed imaging robot. This tool enabled them to simultaneously track over 500,000 fungal nodes—points where mycelial filaments intersect and interact—and analyze approximately 100,000 cytoplasmic flow trajectories, revealing the internal movement of nutrients and carbon within the network.

Unlike many biological organisms whose growth remains exponential as long as resources are available, the studied mycorrhizal fungi adopt a remarkably different strategy: they self-regulate their growth. After the passage of a propagating front, the fungal network reaches a density limit that is independent of resource availability. Instead of continuously expanding, the fungi redirect the carbon obtained from the plant toward exploring new areas. This means that rather than maximizing immediate growth, they optimize their spatial expansion, which in turn enhances their long-term ability to exchange and capture carbon.

Additionally, the study measured the growth rate of the mycorrhizal network, which remains constant over time. This indicates the fungi's need to maintain efficient resource transport within the network. By analyzing cytoplasmic flows inside the mycorrhizal fungi, researchers observed a continuous bidirectional transport between the fungi and plant roots—evidence of the active exchange that sustains this symbiotic relationship. The organization of these flows follows principles comparable to a highly sophisticated and highly efficient logistical supply chain, shaped by hundreds of millions of years of natural selection.

These networks play a crucial role as entry points for carbon into global soils, absorbing approximately 13 billion tons of CO₂ each year—equivalent to one-third of global energy-related emissions. Despite their significance, the complexity and vast reach of these fungal networks had remained poorly understood. This study provides a detailed look at how mycorrhizal fungi construct and optimize their networks to ensure efficient nutrient exchange, ultimately influencing ecosystem function and global carbon cycles.

The discovery of these underground engineering mechanisms sheds new light on the complexity and ingenuity of the interactions that shape ecosystems. Understanding how these fungal networks organize, evolve, and optimize resource exchange allows us to further explore the incredible intelligence of living systems and the fundamental role of unseen organisms in structuring the natural world. These findings also offer new insights into the carbon dynamics in soil, a critical factor in the face of current environmental changes. By unveiling these natural strategies for carbon transport and storage, this research paves the way for rethinking how we integrate these underground networks into soil and ecosystem management in the future.

Collaboration : The work has been done in collaboration with other international research institutions, such as the team of Toby Kiers and Tom Shimizu (VU & AMOLF, Amsterdam, NL) and the team of Howard Stone (Princeton University, NJ, USA)..

Pictures and Video Credits : Loreto Oyarte Galvez (AMOLF & VU, Amsterdam)

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References :
Oyarte Galvez, L., Bisot, C., Bourrianne, P. et al. A travelling-wave strategy for plant–fungal trade. Nature 639, 172–180 (2025). https://doi.org/10.1038/s41586-025-08614-x

NY Times papre : https://www.nytimes.com/2025/03/01/science/climate-mycorrhizal-fungus-networks.html

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Contact :
Philippe Bourrianne (PMMH, ESPCI Paris) : philippe.bourrianne@espci.fr

Swelling and Evaporation Sculpt the Surface of Grafted Hydrogel Films

Paul Turpault d'Huve — 2025-03-18T16:09:38Z

Langmuir 2025, 41, 4, 2400–2410

Soft and deformable materials are ubiquitous, ranging from living organisms such as bacteria to inanimate substances like clay. They are also found in everyday objects like sponges and in complex synthetic materials such as foams and polymer networks. These materials, known as poroelastic, combine elasticity with the ability to absorb solvents.

In a recent study, researchers [1] investigated the behavior of PNIPAM, a polymer that can swell up to four times its size in water to form a hydrogel. When grafted onto a rigid substrate, it is used in microfluidic valves, single-cell trapping, controlled drug release, and cell culture.

However, when attached to a rigid surface, the gel's swelling is constrained, leading to the formation of surface patterns. Once formed, these patterns evolve during drying—a phenomenon that had not been well understood until now. The researchers conducted a systematic characterization of the gel's structures and mechanical properties under both wet and dry conditions.

One of the challenges was studying these extremely soft surfaces, which have a Young's modulus in the kilopascal range. By developing a specialized protocol using atomic force microscopy (AFM), the results showed that the distribution of the Young's modulus follows the swollen-state surface topography, revealing a heterogeneous solvent distribution.

The study highlights a wide range of patterns that depend on the film thickness and drying conditions. By identifying the mechanisms behind these formations, the researchers pave the way for improved control of hydrogel materials for advanced applications in biomedicine and surface engineering.

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References
Swelling and Evaporation Determine Surface Morphology of Grafted Hydrogel Thin FilmsCl, Caroline Kopecz-Muller, Clémence Gaunand, Yvette Tran, Matthieu Labousse, Elie Raphaël, Thomas Salez, Finn Box, Joshua D. McGraw, Langmuir, 2025.
https://doi.org/10.1021/acs.langmuir.4c04025

Contact
Scientific communication from ESPCI Paris - PSL: Paul Turpault paul.turpault@espci.fr

[1] This research was conducted by the Gulliver Laboratory and the SIMM Laboratory at ESPCI Paris – PSL / CNRS, in collaboration with the University of Bordeaux.

When Evolution Learns to Evolve

Paul Turpault d'Huve — 2025-02-24T20:50:46Z

Evolution is often seen as a blind process, driven by natural selection and random mutations. However, a study conducted by researchers [1] from ESPCI Paris - PSL and the Max Planck Institute challenges this perspective. Over three years, they tracked the evolution of a bacterial lineage, identifying and analyzing more than 500 mutations. Their research shows that natural selection not only favors beneficial mutations but can also shape genetic mechanisms to enhance an organism's ability to evolve.

In this experiment, bacteria had to alternate between two phenotypic states to survive. Lineages unable to mutate efficiently disappeared, while those that adapted quickly took their place. An unexpected phenomenon emerged: a hyper-mutable locus—a specific region of the genome—evolved to facilitate these transitions. Through the duplication of a short DNA sequence, this locus experienced a mutation rate increase of 10,000-fold, resembling the "contingency loci" found in pathogenic bacteria.

This result is based on a key principle: in a fluctuating environment, lineages that are better at generating adaptive variation survive and spread. Over many generations, this dynamic shapes the relationship between genotype and phenotype. Beneficial mutations from the past become more accessible, making evolution appear less random than previously thought.

This study demonstrates how selection can embed evolutionary history into genetic architecture, optimizing the adaptability of lineages. Beyond bacteria, these findings shed light on how certain pathogens evade immune defenses and highlight a fundamental mechanism of evolution—one that, over time, refines its own processes.

Figure 1. Lineage Selection (A) Experimental protocol where a lineage alternates between CEL+ (yellow) and CEL– (blue) phenotypes through mutation. Each cycle starts with a single CEL+ genotype, followed by the selection of a CEL– mutant, and then a return to CEL+. Extinction occurs if the transition fails. (B) Schematic representation of competition among lineages in a meta-population, where only those capable of mutating between CEL+ and CEL– survive and become established.

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Références :
Michael Barnett et al.,Experimental evolution of evolvability. Science 387, eadr2756(2025). DOI:10.1126/science.adr2756
Perspective, Enabling evolvability to evolve, A multilevel population architecture enables bacteria to evolve increased adaptability

Contact :
Scientific communication of ESPCI Paris - PSL : Paul Turpault - paul.turpault@espci.fr

[1] Paul B. Rainey, laboratoire CBI de l'ESPCI Paris – PSL et Max Planck Institute for Evolutionary Biology ; Michael Barnett et Lena Meister du Max Planck Institute for Evolutionary Biology.