Assessing the impact of control and prevention strategies on zoonotic diseases in human populations requires the use of formal modelling frameworks, integrating animal, environmental and human data. However, such quantitative “One Health” approaches to guide public health interventions are, to date, overlooked. Their implementation could be facilitated by improved access to epidemiological, demographic, and contact data on different hosts, by improved training of epidemiologists and modellers through relevant multidisciplinary research career paths, and finally by improving institutional support for better visibility.
EvoDevo called homeotic genes "architect genes" because they "control" "body plans". The first metaphor involves purposefulness and brings finalism; the second one is cybernetic; the third one is idealistic/platonic. These are three ways of thinking that are incompatible with today's evolutionary theory. Using such ordering causal factors, EvoDevo partly stayed outside biology-and evolution as well-because in biology, order is not causal: it is a consequence that we need to explain. Natural selection is one of the concepts explaining the rise of apparent short-term biological order, or regularities. We no longer need the verb "to control" [Nijhout, Prog. Biophys. Mol. Biol., 169-170 (2022)]. Since genes are controlled [Noble, Interface Focus, 7 (2017)], just as much as they control, the notion of control in this context is not appropriate. It would be better to speak of "contribution". Natural selection and descent with modification, the two pillars of the Darwinian approach to life [Gayon, C. R. Palevol, 8 (2009)], are entering the soma. They are not restricted to the functioning of the adult soma, but also to the entire developing soma, avoiding "adultocentrism" [Minelli, Toward a Theory of Development (2014)]. The first pillar, natural selection within the body, anticipated by [Roux, Der Kampf der Teile im Organismus: Ein Beitrag zur Vervollständigung der Mechanischen Zweckmässigkeitslehre (1881); Roux, La lutte des parties dans l'organisme (2013)], but occulted during the past century [Heams, La lutte des parties dans l'organisme (2013b)], is now helping to explain cancer dynamics, aging, neurogenesis, etc. With the second pillar, it is now possible to construct the phylogeny of cells of a single developing organism, or to perform a phylogenetic analysis of metastases from a single patient. Ontogenesis and phylogenesis are no more two distinct processes: natural selection and descent with modification both contribute to explain both the developing individual and its stability, as well as the regularity of individuals of a same population from which we name species. The two pillars of evolutionary theory-descent with modification and natural selection-do occur within the developing organism itself and the resulting phenomenon is ontophylogenesis [Kupiec, L'ontophylogenèse. Évolution des espèces et développement de l'individu (2012)], which is actually studied by EvoDevo.
For decades, discussions about the evolution of species overlooked microorganisms. Over a century ago, Neisser and Massini isolated a coliform bacterium that appeared to acquire mutations adapting it to its environment, naming it Bacterium coli mutabile to reflect this feature. With the advent of molecular biology, these widely debated experiments were subsequently forgotten. Here, we present the history of an experiment that reproduces their observations in a modern context where it has become possible to identify the nature of these mutations down to the nucleotide level. Its findings demonstrate that the transcription of gene families that ensure the long-term maintenance of the metabolism of ageing cells is a direct source of adaptive mutations: this process enables bacteria to identify previously unexploited environmental factors that can now support growth. We propose that the driving force behind this adaptation is the spontaneous dehydration/deamidation of polypeptide chains, which dictates an intrinsic lifespan for every protein. This universal mechanism of inevitable protein ageing necessitates their re-synthesis to maintain their function; however the transcription process, which involves opening the DNA double helix, is locally mutagenic. Thus, as bacteria age, the continuous re-synthesis of some of the proteins that perform the functions enabling survival triggers a local mutagenic process. This yields genetic variants, some of which may be beneficial and are therefore retained.
Adaptation is a polysemous word referring both to the state of being adapted and to the selection processes leading to this state. However, considering population adaptation only as an ultimate achievement in a static rather than dynamic perspective may lead to a double misperception: (i) that all adapted populations have depleted variation of adaptive traits and, therefore, low evolvability, and (ii) that adaptation systematically requires many generations. This static vision of adaptation as an achievement is particularly inappropriate for long-lived organisms like trees that continuously respond to selection and retain high levels of adaptive trait variation. This review proposes a baseline for a process-based approach of adaptation in trees, shedding new light on current challenges for forest management and forest genetic resources conservation in the context of global change.A first general section uses the genes-traits-fitness mapping framework to explore the effect of selection on different types of traits, depending on their links to other traits and fitness. In a second section, trait variation and coordination patterns observed in forest trees are interpreted in terms of biological constraints and response to selection. A third section investigates, for trees, how the genes-traits-fitness map varies in space and time with environmental conditions and developmental stages, resulting in spatiotemporal variability of selection. A fourth section reviews the impacts of forestry interventions on trait variation and selection. The conclusive section illustrates the integration of selection as a dynamic and partly manageable process in management thinking for forest genetic resource sustainable use and conservation.
L’augmentation de la concentration atmosphérique de CO 2 et des températures ainsi que la modification des régimes hydriques constituent des déterminants majeurs du fonctionnement et de la productivité des agroécosystèmes. Si les effets de chacun de ces facteurs ont été largement étudiés individuellement, leur action conjointe reste encore mal comprise, alors même que ces facteurs interagissent étroitement dans les conditions climatiques futures. Cet article propose une synthèse des connaissances actuelles sur les impacts combinés de l’élévation de CO 2 , des températures et du déficit hydrique sur les plantes cultivées, avec un accent particulier sur le blé. Après un état des lieux des dispositifs expérimentaux mobilisés pour étudier ces interactions, nous analysons les réponses écophysiologiques et agronomiques des plantes à différentes combinaisons de facteurs climatiques, en distinguant les effets propres, les interactions et les mécanismes de compensation. Les résultats issus de synthèses et méta-analyses récentes mettent en évidence une forte variabilité des réponses, dépendante des espèces, des génotypes, des stades phénologiques et des modalités expérimentales. Les résultats expérimentaux, tous dispositifs confondus, montrent notamment que l’effet fertilisant du CO 2 ne compense pas de manière générale les impacts négatifs des stress hydriques et thermiques, en particulier lorsque ceux-ci sont combinés. Enfin, l’article discute des implications de ces résultats pour la modélisation des cultures et l’anticipation des trajectoires de productivité des agroécosystèmes dans un contexte de changement climatique, en soulignant la nécessité d’intégrer explicitement les interactions entre facteurs climatiques, processus biologiques et variabilité génétique.
Dans le cadre de sa mission de conseil auprès des pouvoirs publics, l’Académie des sciences ne formalise son implication dans les questions de défense qu’en 1992, par la création d’un comité Science technologie et stratégie en lien avec le ministère de la Défense. Ce comité s’intéresse à tous les aspects de la défense. La question des menaces biologiques et des relations biologie-défense y est donc évoquée dans un cadre général. Après l’arrêt des activités de ce comité en 1997, l’Académie crée en 2004 un comité indépendant du ministère, le comité Science et sécurité, vocable incluant notamment la question de la sécurité biologique dans son acception la plus large, dont la défense. Dans la pratique, ce comité oriente progressivement ses travaux sur la biologie, avec la publication en 2008 d’un ouvrage fondateur, Les menaces biologiques , dont une des recommandations principales est la création d’un comité scientifique de surveillance pour la biosécurité. L’Académie va ensuite œuvrer pour cette création, qui sera actée par le décret du 31 août 2015 portant création du Conseil national consultatif pour la biosécurité (CNCB). Placé auprès du Premier ministre, le CNCB est un organisme paritaire dont l’Académie propose les membres scientifiques. Entre-temps, en 2014, le comité Science et sécurité de l’Académie est devenu le comité Science et biosécurité. Il travaille depuis en étroite collaboration avec le CNCB, dans un monde où l’accélération de l’évolution scientifique facilite l’accès à des technologies potentiellement duales, et à des formes sophistiquées de terrorisme.
Dans cet article, nous illustrons l’intérêt de coupler théorie écologique et sylviculture au travers de l’exemple de la sylviculture mélangée à couvert continu et de l’utilisation d’un modèle de dynamique forestière essentiellement mobilisé pour aborder des questions de recherche en écologie et biogéographie (MATREEX). Dans un contexte où la diversification représente une stratégie promue pour l’adaptation des forêts au changement climatique, nous explorons comment différents mécanismes de coexistence des espèces (fréquence-dépendance négative, non-linéarité relative, compromis recrutement-survie) peuvent être traduits en actions sylvicoles et testons leur efficacité en termes de maintien de mélanges. Notre étude porte sur deux mélanges connus pour être difficiles à conduire en sylviculture : entre chêne sessile ( Quercus petraea (Matt.) Liebl.) et hêtre commun ( Fagus sylvatica L.) d’une part, et entre sapin pectiné ( Abies alba Mill.) et pin sylvestre ( Pinus sylvestris L.) d’autre part. Nous montrons que la sélection préférentielle de l’espèce la plus abondante (fréquence-dépendance négative), par ailleurs aisée à mettre en œuvre et déjà appliquée en gestion forestière, s’avère très efficace pour le maintien de l’espèce la moins compétitive dans le mélange. Les autres mécanismes testés n’exercent qu’une influence limitée sur les taux de mélange. Bien que ces résultats doivent être interprétés avec précautions en tenant compte des limites du modèle utilisé, ils permettent de dégager de premiers éléments à approfondir avec d’autres approches et de faire émerger des hypothèses à tester in situ .
Les changements environnementaux, notamment climatiques, exercent une pression inédite sur la biodiversité forestière. Or celle-ci joue un rôle clé dans le fonctionnement des écosystèmes forestiers et la qualité des services écosystémiques qu’ils rendent aux sociétés humaines. L’adaptation spontanée ou « facilitée » des forêts aux changements climatiques représente un défi inédit pour la science et l’ingénierie forestière. Un enjeu est de mobiliser la biodiversité pour accroître la résilience des écosystèmes forestiers et préserver leur intégrité fonctionnelle face à l’intensification des stress et la récurrence des perturbations. Trois préalables indispensables sont d’abord explicités : (i) appréhender la biodiversité comme l’héritage d’une histoire locale, régionale et globale ; (ii) considérer la biodiversité comme un attribut fonctionnel de l’écosystème ; (iii) regarder la biodiversité comme un assemblage d’espèces déterminé par des pressions naturelles et anthropiques qui affecte en retour la résilience de l’écosystème à ces derniers. Nous analysons ensuite les conséquences prévisibles sur la biodiversité des trois stratégies actuellement mises en œuvre pour l’adaptation des forêts en France métropolitaine : laisser la forêt en évolution libre ; gérer la forêt de manière à accroître sa résilience ; et remplacer les forêts existantes par des plantations d’arbres (souvent exotiques) supposés mieux adaptés au climat de demain. Pour chaque stratégie, nous esquissons un rapport bénéfices/risques. Nous concluons sur l’impérative nécessité de refonder l’ingénierie forestière sur les apports scientifiques de l’écologie fonctionnelle, où la biodiversité — qui ne se limite pas au nombre d’espèces d’arbres — n’est pas un frein à la gestion forestière, mais un levier d’adaptation.
In this article, we illustrate the value of combining ecological theory and silviculture through the example of continuous cover forestry in mixed stands and the use of a forest dynamics model that addresses research questions in ecology and biogeography (MATREEX). In a context where diversification is a strategy promoted for the adaptation of forests to climate change, we explore how different species coexistence mechanisms (negative frequency dependence, relative nonlinearity, recruitment-survival trade-off) can be translated into silvicultural actions and test their effectiveness in terms of species coexistence. Our study focuses on two types of mixed stands known to be difficult to manage between sessile oak (Quercus petraea (Matt.) Liebl.) and common beech (Fagus sylvatica L.), on the one hand, and silver fir (Abies alba Mill.) and Scots pine (Pinus sylvestris L.), on the other hand.We show that preferential selection of the most abundant species (negative frequency dependence), which is easy to implement and already used in forest management, is very effective in favouring the least competitive species in the stand. The other mechanisms tested have only a limited influence on species proportions. Although these results must be interpreted with caution, taking into account the limitations of the model used, they provide initial findings that can be explored further using other approaches and give rise to hypotheses that can be tested in situ.
Cet article se propose de résumer des modèles mathématiques de l’architecture fonctionnelle du cortex visuel primaire (aire V 1) de certaines espèces, et en particulier de leur structuration en hypercolonnes d’orientation. Les cartes d’orientaion y sont interprétées comme des champs de phases et leurs « pinwheels » comme des singularités.
Environmental changes, including climate change, put forest biodiversity under an unprecedented pressure. Yet, biodiversity plays a key role in the functioning of forest ecosystems and the quality of the services they provide to human societies. The spontaneous or "facilitated" adaptation of forests to climate change represents a new challenge for forest science and engineering. One challenge is to mobilize biodiversity to increase the resilience of forest ecosystems and preserve their functional integrity in the face of intensifying stresses and increased disturbance frequency. I first discuss three prerequisites: (i) understanding biodiversity as the legacy of local, regional, and global histories; (ii) considering biodiversity as a functional attribute of forest ecosystems; (iii) considering biodiversity as species assemblages that are patterned by natural and anthropogenic forcings that, in turn, affect the ecosystem's resilience to these forcings. I then analyze the foreseeable consequences for biodiversity of the three strategies currently implemented for forest adaptation in metropolitan France: free evolution of forests; managing forests to increase their resilience; and replacing existing forests with plantations of (often exotic) tree species supposed to be better adapted to forthcoming climate conditions. For each strategy, I outline a benefit/risk assessment. I conclude with the imperative need to revisit forest engineering based on the scientific outputs of functional ecology, where biodiversity-which is not limited to the number of tree species-is not an obstacle to forest management, but a lever for adaptation.
Rising atmospheric CO2 concentrations and temperatures, as well as changes in water regimes, are major determinants of the functioning and productivity of agroecosystems. Although the individual effects of each of these factors have been extensively studied, their combined action remains poorly understood, despite the fact that these factors interact closely to shape future climate conditions. This article provides a synthesis of current knowledge on the combined impacts of rising CO2, temperatures and water deficiency on crop plants, with a particular focus on wheat. Following a review of the experimental setups used to study these interactions, we analyse the ecophysiological and agronomic responses of plants to different combinations of climatic factors, distinguishing between specific effects, interactions and compensatory mechanisms. Results from recent syntheses and meta-analyses highlight a high degree of variability in responses, depending on species, genotypes, phenological stages and experimental conditions. Experimental results, across all experimental setups, show in particular that the fertilising effect of CO2 does not generally compensate for the negative impacts of water and heat stress, particularly when these are combined. Finally, this article discusses the implications of these results for crop modelling and the prediction of agroecosystem productivity trajectories in a climate change context, emphasising the need to explicitly integrate interactions between climatic factors, biological processes and genetic variability.
Major evolutionary transitions in individuality occur when previously independent entities become components of a new unit whose parts share a reproductive fate. Most discussions focus on transitions arising through the integration of independent lineages. Less attention has been given to the possibility that transitions might originate from within a lineage, where internally generated components become incorporated into the parent-offspring system and inherited as part of a higher-level individual. Such cases would constitute what I term autogenic transitions in individuality. Biological and cultural precedents in which lineages generate novel entities that subsequently influence their own evolution are first examined. In most cases such innovations remain embedded within existing individuals, although transmissible cancers demonstrate that internally generated lineages can also form distinct Darwinian populations. These comparisons clarify the conditions under which internally generated systems might give rise to new evolutionary individuals. The emergence of artificial intelligence (AI), and its growing entanglement with human development and social organisation, make it timely to examine such possibilities. Three routes are considered: (1) centralised, non-replicating AI systems that influence human evolution through persistent creation of conditions that cause selection to work at the collective level; (2) replicating AI lineages capable of entering egalitarian associations with humans; (3) AI systems transmitted across generations as components of the human developmental system. The first alters selection without generating reproduction of the composite, whereas the latter two create conditions under which humans and AI could form evolving composite lineages. Autogenic transitions therefore extend evolutionary theory by identifying routes by which new evolutionary individuals may arise when components generated within a lineage become incorporated into systems of reproduction and inheritance, and by helping to recognise plausible transitions that might otherwise be overlooked because such components first appear as subordinate products or tools rather than as candidate parts of a new evolutionary individual.
Climate change is already affecting French forests: rising temperatures, altered precipitation, and more frequent extreme events are driving shifts in species distributions, reduced productivity, and increased tree mortality. Anticipating future forest composition requires understanding species' exposure to future climatic conditions, their sensitivity to these conditions, and their capacity to adapt or migrate. Regional contrasts are marked, with stronger warming and drying in northeastern and Mediterranean regions, while parts of western France are comparatively less affected. Observations show high vulnerability of temperate species such as Fagus sylvatica and Picea abies, whereas Mediterranean species (e.g. Pinus pinaster, P. halepensis) appear more resistant at present.Future changes will depend on climate change evolution intensity, site and stand characteristics, species composition, and adaptive capacity. Initially, adaptive management-adjusting stand structure, promoting diversity, and managing density, water, and species selection-can mitigate impacts and buy time. Under higher vulnerability, species replacement may become necessary-ideally by favoring drought-tolerant species already present through natural regeneration, or otherwise through assisted migration using drought-adapted provenances of native species or non-native species with suitable traits. Uncertainties about ecosystem resilience and the effectiveness of management measures underline the need for integrative, site-specific strategies to sustain ecosystem services and effectively guide future forest composition under ongoing climate change.
Organs and tissues consist of a precise arrangement of different cell types, all playing a specific role to fulfil the biological function of the tissue. Small changes in cellular phenotypes or behaviour can lead to developmental defects, tissue malfunctions or the emergence of diseases. Therefore, tissue integrity, health and function are maintained through different quality control mechanisms. One highly conserved mechanism is cell competition, through which cells of reduced fitness are eliminated. Cells can employ various strategies to eliminate each other. Those include the exertion of mechanical forces, but its role in determining the competition outcome remains unclear. Here, we report that heterogeneities in force transmission capabilities mediated by cell-cell adhesion differences lead to cell competition. We show that increased force transmission endows collectives of cells with a fitness advantage, as it provides increased resistance to elimination forces. Elimination forces are generated from large stress fluctuations, emerging at the interfaces of competing cell populations. Besides promoting the removal of unfit cells in a wide range of biological conditions where local cell-cell adhesion heterogeneities are observed, this mechanism might be of general importance for the generation and maintenance of tissue boundaries.
This article aims to summarize the mathematical models of the functional architecture of the primary visual cortex (area V1) in certain species, and in particular its organization into orientation hypercolumns. The orientation maps are interpreted here as phase fields and their "pinwheels" as singularities.
Viruses are obligate symbionts of cellular life forms that can replicate only within host cells and typically form virions (virus particles) to spread among host organisms. Virions numerically dominate the biosphere, exceeding the number of cells several-fold, and also comprise the main reservoir of genetic diversity on earth. Nearly all organisms host multiple, diverse viruses. Unlike cellular organisms, viruses have genomes (genetic information carriers incorporated into virions) that consist of all forms of RNA and DNA, suggesting an evolutionary connection between extant viruses and the primordial replicator pool. Lately, extensive mining of metagenomes and metatranscriptomes has dramatically expanded the world of viruses (virosphere), revealing an unsuspected and unprecedented diversity. Viruses share no universal genes and have multiple origins. However, about 15 viral hallmark genes each bring together multiple, diverse groups of viruses, and many other genes are shared within such groups. Evolution of viruses is inextricably intertwined with the evolution of their hosts. A key aspect of virus-host coevolution is the arms race resulting in accelerated evolution on both sides, especially of host defenses and viral counter-defenses. A complementary, prominent feature of this coevolution is exaptation, whereby viral genes are coopted by the hosts for antiviral defense and other roles, and conversely, viruses capture host genes for diverse functions in virus replication, virion morphogenesis and virus-host interaction. In this review, we attempt a synthesis of the current understanding of the global organization of the virosphere, the major trends and events in the evolution of viruses, and the high-level taxonomy of viruses.
In the current epoch of profound anthropogenic transformations of ecosystems, managing wildlife cannot be reduced to simple technical adjustments in response to social tensions or conflicts. This article proposes a shift in perspective based on three principles-ecological solidarity, interspecies reciprocity and environmental justice-to reconsider the conditions of coexistence between humans and wildlife. These principles are not limited to damage prevention; they can also open up political spaces for diverse living beings and their relations. We therefore present a framework for analyzing socio-ecological viability consisting of four dimensions: ecological interdependence, ethical-political commitment, relationship quality, and institutional arrangement fairness. Through three case studies in France involving wolves (Canis lupus), wild boars (Sus scrofa) and greater flamingos (Phoenicopterus roseus), we examine three contrasting management strategies: conflict and polarization, pragmatic hunting and symbiotic negotiation-processes of mutual adjustment in shared environments. These cases do not describe fixed management regimes, but rather shifting configurations that reveal forms of power, situated knowledge and animal agency. Our analysis reveals the necessity of a wildlife governance that is more attentive to attachments, yet also more demanding in terms of reciprocity, and capable of recognizing the contributions of non-humans to shared environments. Transitioning from a logic of compensation to a policy of co-viability therefore necessitates supporting practices that foster a shared habitability and habitable futures for humans and other living beings alike.
Les champignons sylvicoles jouent un rôle majeur dans le fonctionnement et la durabilité des écosystèmes forestiers. Cet article se propose de faire une synthèse des connaissances actuelles sur la biologie et l’écologie des deux guildes de champignons prédominantes en forêt : les champignons saprotrophes, qui assurent la décomposition des détritus végétaux et de la matière organique du sol, et les champignons symbiotiques mycorhiziens, qui stimulent la croissance des arbres. Je présenterai les facteurs déterminant la diversité et la dynamique des communautés fongiques des sols forestiers sous contrainte climatique. Enfin, j’aborderai brièvement les programmes de recherche visant à définir les conditions d’utilisation du microbiote des arbres, et en particulier des symbiotes mycorhiziens, dans les projets de plantation et de migration assistée d’essences sylvicoles. La mycorhization contrôlée permet la production de jeunes plants forestiers mycorhizés avec des souches fongiques sélectionnées, améliorant ainsi la nutrition minérale et hydrique des plants, stimulant la croissance juvénile et renforçant la résistance à la sécheresse et aux agents pathogènes. Elle est également déployée en trufficulture et dans la production de champignons comestibles.
