Bet-hedging strategies in expanding populations

In ecology, species can mitigate their extinction risks in uncertain environments by diversifying individual phenotypes. This observation is quantified by the theory of bet-hedging, which provides a reason for the degree of phenotypic diversity observed even in clonal populations. Bet-hedging in well-mixed populations is rather well understood. However, many species underwent range expansions during their evolutionary history, and the importance of phenotypic diversity in such scenarios still needs to be understood. In this paper, we develop a theory of bet-hedging for populations colonizing new, unknown environments that fluctuate either in space or time. In this case, we find that bet-hedging is a more favorable strategy than in well-mixed populations. For slow rates of variation, temporal and spatial fluctuations lead to different outcomes. In spatially fluctuating environments, bet-hedging is favored compared to temporally fluctuating environments. In the limit of frequent environmental variation, no opportunity for bet-hedging exists, regardless of the nature of the environmental fluctuations. For the same model, bet-hedging is never an advantageous strategy in the well-mixed case, supporting the view that range expansions strongly promote diversification. These conclusions are robust against stochasticity induced by finite population sizes. Our findings shed light on the importance of phenotypic heterogeneity in range expansions, paving the way to novel approaches to understand how biodiversity emerges and is maintained.This study has been partially financed by the Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía and European Regional Development Fund (ERDF), ref. SOMM17/6105/UGR (to MAM)

Quenched disorder forbids discontinuous transitions in nonequilibrium low-dimensional systems

Quenched disorder affects significantly the behavior of phase transitions. The Imry-Ma-Aizenman-Wehr-Berker argument prohibits first-order or discontinuous transitions and their concomitant phase coexistence in low-dimensional equilibrium systems in the presence of random fields. Instead, discontinuous transitions become rounded or even continuous once disorder is introduced. Here we show that phase coexistence and first-order phase transitions are also precluded in nonequilibrium low-dimensional systems with quenched disorder: discontinuous transitions in two-dimensional systems with absorbing states become continuous in the presence of quenched disorder. We also study the universal features of this disorder-induced criticality and find them to be compatible with the universality class of the directed percolation with quenched disorder. Thus, we conclude that first-order transitions do not exist in low-dimensional disordered systems, not even in genuinely nonequilibrium systems with absorbing states

Ocean currents promote rare species diversity in protists

Oceans host communities of plankton composed of relatively few abundant species and many rare species. The number of rare protist species in these communities, as estimated in metagenomic studies, decays as a steep power law of their abundance. The ecological factors at the origin of this pattern remain elusive. We propose that chaotic advection by oceanic currents affects biodiversity patterns of rare species. To test this hypothesis, we introduce a spatially explicit coalescence model that reconstructs the species diversity of a sample of water. Our model predicts, in the presence of chaotic advection, a steeper power law decay of the species abundance distribution and a steeper increase of the number of observed species with sample size. A comparison of metagenomic studies of planktonic protist communities in oceans and in lakes quantitatively confirms our prediction. Our results support that oceanic currents positively affect the diversity of rare aquatic microbes

Enhanced mutation rate, relaxed selection, and the ‘domino effect’ drive gene loss in Blattabacterium, a cockroach endosymbiont

Intracellular endosymbionts have reduced genomes that progressively lose genes at a timescale of tens of million years. We previously reported that gene loss rate is linked to mutation rate in Blattabacterium, however, the mechanisms causing gene loss are not yet fully understood. Here, we carried out comparative genomic analyses on the complete genome sequences of a representative set of 67 Blattabacterium strains, with sizes ranging between 511kbp and 645kbp. We found that 200 of the 566 analysed protein-coding genes were lost in at least one lineage of Blattabacterium, with the most extreme case being one gene that was lost independently in 24 lineages. We found evidence for three mechanisms influencing gene loss in Blattabacterium. First, gene loss rates were found to increase exponentially with the accumulation of substitutions. Second, genes involved in vitamin and amino acid metabolism experienced relaxed selection in Cryptocercus and Mastotermes, possibly triggered by their vertically-inherited gut symbionts. Third, we found evidences of epistatic interactions among genes leading to a \u27domino effect\u27 of gene loss within pathways. Our results highlight the complexity of the process of genome erosion in an endosymbiont

Intermittent percolation and the scale-free distribution of vegetation clusters

Understanding the causes and effects of spatial vegetation patterns is a fundamental problem in ecology, especially because these can be used as early predictors of catastrophic shifts such as desertification processes. Empirical studies of the vegetation cover in some areas such as drylands and semiarid regions have revealed the existence of vegetation patches of broadly diverse sizes. In particular, the probability distribution of patch sizes can be fitted by a power law, i.e. vegetation patches are approximately scale free up to some maximum size. Different explanatory mechanisms, such as plant–plant interactions and plant-water feedback loops have been proposed to rationalize the emergence of such scale-free patterns, yet a full understanding has not been reached. Using a simple model for vegetation dynamics, we show that environmental temporal variability—a well-recognized feature of semiarid environments—promotes in a robust way (i.e. for a wide range of parameter values) the emergence of vegetation patches with broadly distributed cluster sizes. Furthermore, this result is related to a percolation phenomenon that occurs in an intermittent or fluctuating way. The model also reveals that the power-law exponents fitting the tails of the probability distributions depend on the overall vegetation-cover density, in agreement with empirical observations. This supports the idea that environmental variability plays a key role in the formation of scale-free vegetation patterns. From a practical viewpoint, this may be of importance to predict the effects that changes in environmental conditions may have in real ecosystems. From a theoretical side, our study sheds new light on a novel type of percolation phenomena occurring under temporally-varying external conditions, that still needs further work to be fully characterized.Spanish Ministry and Agencia Estatal de investigacion (AEI) FIS2017-84256-PJunta de AndaluciaEuropean Union (EU) A-FQM-175-UGR18 SOMM17/6105/UG

Increased Mutation Rate Is Linked to Genome Reduction in Prokaryotes

The evolutionary processes that drive variation in genome size across the tree of life remain unresolved. Effective population size (Ne) is thought to play an important role in shaping genome size [1, 2, 3]—a key example being the reduced genomes of insect endosymbionts, which undergo population bottlenecks during transmission [4]. However, the existence of reduced genomes in marine and terrestrial prokaryote species with large Ne indicate that genome reduction is influenced by multiple processes [3]. One candidate process is enhanced mutation rate, which can increase adaptive capacity but can also promote gene loss. To investigate evolutionary forces associated with prokaryotic genome reduction, we performed molecular evolutionary and phylogenomic analyses of nine lineages from five bacterial and archaeal phyla. We found that gene-loss rate strongly correlated with synonymous substitution rate (a proxy for mutation rate) in seven of the nine lineages. However, gene-loss rate showed weak or no correlation with the ratio of nonsynonymous/synonymous substitution rate (dN/dS). These results indicate that genome reduction is largely associated with increased mutation rate, while the association between gene loss and changes in Ne is less well defined. Lineages with relatively high dS and dN, as well as smaller genomes, lacked multiple DNA repair genes, providing a proximate cause for increased mutation rates. Our findings suggest that similar mechanisms drive genome reduction in both intracellular and free-living prokaryotes, with implications for developing a comprehensive theory of prokaryote genome size evolution

¿Qué queda de mí?

Este libro es una reclamación a quienes hemos sido, somos o seremos docentes. A quienes no hemos respetado a las personas que se han puesto junto a nosotros y nosotras, confiando su bien más preciado: la libertad. Estas páginas denuncian cada vez que convertimos una visión en la visión, una emoción en la emoción, un saber en el saber, un comportamiento en el comportamiento. Es un grito contra la imposición, la normalización, la neutralización y la universalización de una perspectiva particular. Una pugna contra cada proceso que no se ha conectado con las vidas de los aprendices. Un texto colaborativo realizado por alumnado de Educación y Cambio Social en el Grado en Educación Infantil de la Universidad de Málaga y coordinado por Ignacio Calderón Almendros

Update process of the national agenda for public health research 2021-2022

Una Agenda Nacional de Investigación en Salud Pública (ANISP) participativa y con priorización temática constituye un elemento estratégico para generar recomendaciones y políticas públicas basadas en evidencia, que impacten positivamente en la salud de las poblaciones y permitan lograr los objetivos sanitarios. En la actualización de la ANISP participaron la Dirección de Investigación en Salud (DIS) del Ministerio de Salud de la Nación (MSAL), a través de la Red Ministerial de Investigación en Salud (REMINSA), y actores de los niveles gubernamentales provinciales y nacionales pertenecientes a los sectores público, privado, de la salud, académico y de investigación. Se adaptó la herramienta original propuesta por la Organización Panamericana de la Salud, utilizada en el proceso en 2019. La actualización abarcó diferentes etapas. La selección de los temas contó con la legitimidad, reconocimiento y participación de los actores vinculados a la salud, a la gestión gubernamental y privada y a la investigación científica; se trabajó de manera federal y transversal, por consenso con las redes provinciales y un Comité Central Asesor en el MSAL. A partir de los lineamientos preliminares obtenidos, se elaboró una encuesta en línea semiestructurada, que fue distribuida a todos los actores federales y recibió 431 respuestas. El proceso resultó en 55 lineamientos priorizados, divididos en 6 áreas temáticas y 33 subtemas, seleccionados por votación según importancia, impacto y factibilidad.A participatory National Public Health Research Agenda (ANISP) with thematic prioritization is a strategic element to generate evidence-based recommendations and public policies that have a positive impact on the health of populations and enable to achieve health objectives. The Directorate of Health Research (DIS) of the Argentine Ministry of Health (MSAL), through the Ministerial Network of Health Research (REMINSA), along with actors from the provincial and national government levels belonging to public, private, health, academic and research sectors participated in the update of the ANISP. They adapted the original tool proposed by the Pan American Health Organization and used in the process in 2019. The update included different stages. The selection of the topics had the legitimacy, recognition and participation of the actors involved, related to health, to government and private management and to scientific research; the work was conducted in a federal and transversal manner by consensus with the provincial networks and a Central Advisory Committee in the MSAL. Based on the preliminary guidelines obtained, a semi-structured online survey was developed and distributed to all federal actors, receiving 431 responses. The process resulted in 55 prioritized guidelines, divided into 6 thematic areas and 33 sub-themes, selected by voting according to importance, impact and feasibility.Fil: Traverso Vior, Natacha. Ministerio de Salud de la Nación; ArgentinaFil: Barrenechea, María del Rosario. Ministerio de Salud de la Nación; ArgentinaFil: Torales, Santiago. Ministerio de Salud de la Nación; ArgentinaFil: Ianovsky, Oscar Gabriel. Ministerio de Salud de la Nación; ArgentinaFil: Lago, Manuel. Ministerio de Salud de la Nación; ArgentinaFil: Carbonelli, Carla. Ministerio de Salud de la Nación; ArgentinaFil: Faletty, Carolina. Gobierno de la Provincia de Buenos Aires. Ministerio de Salud; ArgentinaFil: González Villa Monte, Gabriel. Gobierno de la Ciudad Autónoma de Buenos Aires. Ministerio de Salud; ArgentinaFil: Cabrera, Jorge. Gobierno de la Provincia de Catamarca. Ministerio de Salud.; ArgentinaFil: Sartor, Paula. Gobierno de la Provincia de Chaco. Ministerio de Salud Publica; ArgentinaFil: Sandoval, Alejandra. Gobierno de la Provincia del Chubut. Ministerio de Salud; ArgentinaFil: Mercado, Daniel. Gobierno de la Provincia de Cordoba. Ministerio de Salud; ArgentinaFil: Andino, Gerardo Marcelo. Gobierno de la Provincia de Corrientes. Ministerio de Salud Pública; ArgentinaFil: Pisarello, María Susana. Gobierno de la Provincia de Corrientes. Ministerio de Salud Pública; ArgentinaFil: Benzi, Patricia. Gobierno de la Provincia de Entre Rios. Ministerio de Salud.; ArgentinaFil: Zamponi, Hernán. Gobierno de la Provincia de Jujuy. Ministerio de Salud; ArgentinaFil: Elorza, Claudia. Gobierno de la Provincia de la Pampa. Ministerio de Salud; ArgentinaFil: Laino, Carlos Horacio. Gobierno de la Provincia de la Rioja Ministerio de Salud Pública; ArgentinaFil: Laconi, Myriam Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Gobierno de la Provincia de Mendoza. Ministerio de Salud Desarrollo Social y Deportes; ArgentinaFil: Martín, María Cristina. Gobierno de la Provincia de Misiones. Ministerio de Salud; ArgentinaFil: Margaría, Laura. Gobierno de la Provincia de Rio Negro. Ministerio de Salud; ArgentinaFil: Oliva, Valeria. Gobierno de la Provincia de Salta. Ministerio de Salud Publica; ArgentinaFil: Pérez Paso, Andrea. Gobierno de la Provincia de San Juan. Ministerio de Salud Publica; ArgentinaFil: Suarez, Elsa Fanny. obierno de la Provincia de San Luis. Ministerio de Salud; ArgentinaFil: Pejkovic, Celina. Gobierno de la Provincia de Santa Cruz. Ministerio de Salud y Ambiente.; ArgentinaFil: Mansilla, Celina. Gobierno de la Provincia de Santa Cruz. Ministerio de Salud y Ambiente.; ArgentinaFil: Perichón, Mario. Centro Único de Ablación e Implante de Órganos; ArgentinaFil: Andrek, Gastón. Hospital de Niños Zona Norte de Rosario; ArgentinaFil: Burgos, Graciela. Gobierno de la Provincia de Santiago del Estero. Ministerio de Salud; ArgentinaFil: Laio, Alejandro. Gobierno de la Provincia de Tierra del Fuego. Ministerio de Salud; Argentin

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality