Evolutionary Scenario Research Articles

Constraints on supermassive black hole binaries from JWST and NANOGrav

We use the recent statistics of dual active galactic nuclei (AGN) in the James Webb Space Telescope (JWST) data at z ∼ 3.4 to address two aspects of the feedback and evolution scenarios of supermassive black hole binaries. We find that the JWST data provide evidence for the members of a binary BH being ‘lit’ at the same time, rather than independently – a scenario which is consistent with gas-rich mergers being responsible for concurrent AGN activity. This conclusion is supported by the recent NANOGrav Pulsar Timing Array (PTA) measurements, whose upper limits on the stochastic gravitational wave strain amplitude lie below those expected from extrapolating the dual AGN fraction. The results indicate either a ‘stalling’ of the binaries at the separations probed by NANOGrav, or rapid gas-driven inspirals.

Emulating the interstellar medium chemistry with neural operators

Context. The study of galaxy formation and evolution critically depends on our understanding of the complex photo-chemical processes that govern the evolution and thermodynamics of the interstellar medium (ISM). In a computational sense, resolving the chemistry is among the weightiest tasks in cosmological and astrophysical simulations. Aims. Astrophysical simulations can include photo-chemical models that allow for a wide range of densities (n), abundances of different species (ni/n) and temperature (T), and plausible evolution scenarios of the ISM under the action of a radiation field (F) with different spectral shapes and intensities. The evolution of such a non-equilibrium photo-chemical network relies on implicit, precise, computationally costly, ordinary differential equations (ODE) solvers. Here, we aim to substitute such procedural solvers with fast, pre-trained emulators based on neural operators. Methods. We emulated a non-equilibrium chemical network up to H2 formation (9 species, 52 reactions) by adopting the DeepONet formalism, namely: by splitting the ODE solver operator that maps the initial conditions and time evolution into a tensor product of two neural networks (named branch and trunk). We used KROME to generate a training set, spanning −2 < log(n/cm−3) ≤ 3.5, log(20) ≤ log(T/K) ≤ 5.5, −6 ≤ log(ni/n) < 0, and adopting an incident radiation field, F, sampled in 10 energy bins with a continuity prior. We separately trained the solver for T and each ni for ≃4.34 GPUhrs. Results. Compared with the reference solutions obtained by KROME for single-zone models, the typical precision obtained is of the order of 10−2, that is, it is 10 times better when using a training that is 40 times less costly, with respect to previous emulators that only considered a fixed F. DeepONet also performs well for T and ni outside the range of the training sample. Furthermore, the emulator aptly reproduces the ion and temperature profiles of photo dissociation regions as well; namely, by giving errors that are comparable to the typical difference between various photo-ionization codes. The present model achieves a speed-up of a factor of 128× with respect to stiff ODE solvers. Conclusions. Our neural emulator represents a significant leap forward in the modelling of ISM chemistry, offering a good balance of precision, versatility, and computational efficiency. Nevertheless, further work is required to address the challenges represented by the extrapolation beyond the training time domain and the removal of potential outliers.

Electrical stimulation of chicken embryo development supports the Inside story scenario of human development and evolution

Animal evolution is driven by random mutations at the genome level. However, it has long been suggested that there exist physical constraints which limit the set of possible outcomes. In craniate evolution, it has been observed that head features, notably in the genus homo, can be ordered in a morphological diagram such that, as the brain expands, the head rocks more forward, face features become less prognathous and the mouth tends to recede. One school of paleontologists suggests that this trend is wired somewhere structurally inside the anatomy, and that random modifications of genes push up or down animal forms along a pre-determined path. No actual experiment has been able to settle the dispute. I present here an experiment of electric stimulation of the head in the chicken embryo which is able to enhance the magnitude of tension forces during development. This experimental intervention causes a correlated brain shrinkage and rotatory movement of the head, congruent with tissue texture, which proves that head dilation and flexure are intimately linked. Numerical modelling explains why the brain curls when it dilates. This gives support to the idea that there exists, in the texture of the vertebrate embryo, a latent dynamic pattern for the observed paleontological trends in craniates towards homo, a concept known as Inside story.

Complete Mitogenome sequencing of the fish louse Argulus japonicus (Crustacea: Branchiura): Comparative analyses and phylogenetic implications.

The fish louse Argulus japonicus, a branchiuran crustacean of the Argulidae family, is attracting increasing attention because of its parasitic tendencies and significant health threats to global fish farming. The mitogenomes can yield a foundation for studying epidemiology, genetic diversity, and molecular ecology and therefore may be used to assist in the surveillance and control of A. japonicus. In this study, we sequenced and assembled the complete mitogenome of A. japonicus to shed light on its genetic and evolutionary blueprint. Our investigation indicated that the 15,045-bp circular genome of A. japonicus encodes 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), and 2 ribosomal RNAs (rRNAs) with significant AT and GC skews. Comparative genomics provided an evolutionary scenario for the genetic diversity of 13 PCGs: all were under purifying selection, with cox1 and nad6 having the lowest and highest evolutionary rates, respectively. Genome-wide phylogenetic trees established a close relationship between species of the families Argulidae (Arguloida) and Armilliferidae (Porocephalida) within Crustacea, and further, A. japonicus and Argulus americanus were determined to be more closely related to each other than to others within the family Argulidae. Single PCG-based phylogenies supported nad1 and nad6 as the best genetic markers for evolutionary and phylogenetic studies for branchiuran crustaceans due to their similar phylogenetic topologies with those of genome-based phylogenetic analyses. To sum up, these comprehensive mitogenomic data of A. japonicus and related species refine valuable marker resources and should contribute to molecular diagnostic methods, epidemiological investigations, and ecological studies of the fish ectoparasites in Crustacea.

Karyotype Diversification and Chromosome Rearrangements in Squamate Reptiles.

Karyotype diversification represents an important, yet poorly understood, driver of evolution. Squamate reptiles are characterized by a high taxonomic diversity which is reflected at the karyotype level in terms of general structure, chromosome number and morphology, and insurgence of differentiated simple or multiple-sex-chromosome systems with either male or female heterogamety. The potential of squamate reptiles as unique model organisms in evolutionary cytogenetics has been recognised in recent years in several studies, which have provided novel insights into the chromosome evolutionary dynamics of different taxonomic groups. Here, we review and summarize the resulting complex, but promising, general picture from a systematic perspective, mapping some of the main squamate karyological characteristics onto their phylogenetic relationships. We highlight how all the major categories of balanced chromosome rearrangements contributed to the karyotype evolution in different taxonomic groups. We show that distinct karyotype evolutionary trends may occur, and coexist, with different frequencies in different clades. Finally, in light of the known squamate chromosome diversity and recent research advances, we discuss traditional and novel hypotheses on karyotype evolution and propose a scenario of circular karyotype evolution.

Inferring current and Last Glacial Maximum distributions are improved by physiology‐relevant climatic variables in cold‐adapted ectotherms

AbstractAimEcological niche‐based models (ENM) frequently rely on bioclimatic variables (BioV) to reconstruct biogeographic scenarios for species evolution, ignoring mechanistic relations. We tested if climatic predictors relevant to species hydric and thermal physiology better proximate distribution patterns and support location of Pleistocene refugia derived from phylogeographic studies.LocationThe Western Palaearctic.TaxonVipera berus and Zootoca vivipara, two cold‐adapted species.MethodsWe used two sets of variables, that is physiologically meaningful climatic variables (PMV) and BioV, in a multi‐algorithm ENM approach, to compare their ability to predict current and Last Glacial Maximum (LGM) species ranges. We estimated current and LGM permafrost extent to address spatially the cold hardiness dissimilarity between both species.ResultsPMV explained more accurately the current distribution of these two cold‐adapted species and identified the importance of summer temperature and solar radiation that constrain activity in cold habitats. PMV also provide a better insight than BioV predictors on LGM distribution. By including notably, the permafrost extent, PMV‐based models gave parsimonious putative arrangement and validity of refugia for each clade and subclade in accordance with phylogeographic data. Northern refugia were also identified from 48 to 52° N for V. berus and from 50 to 54° N for Z. vivipara.Main ConclusionsOur hybrid approach based on PMV generated more realistic predictions for both current (biogeographical validation) and past distributions (phylogeographic validation). By combining constraints during the activity period (summer climatic niche) and those inherent to the wintering period (freeze tolerance), we managed to identify glacial refuges in agreement with phylogeographic hypotheses concerning post‐glacial routes and colonization scenarios.

The pseudoentropy of allele frequency trajectories, the persistence of variation, and the effective population size

To concisely describe how genetic variation, at individual loci or across whole genomes, changes over time, and to follow transitory allelic changes, we introduce a quantity related to entropy, that we term pseudoentropy. This quantity emerges in a diffusion analysis of the mean time a mutation segregates in a population. For a neutral locus with an arbitrary number of alleles, the mean time of segregation is generally proportional to the pseudoentropy of initial allele frequencies. After the initial time point, pseudoentropy generally decreases, but other behaviours are possible, depending on the genetic diversity and selective forces present.For a biallelic locus, pseudoentropy and entropy coincide, but they are distinct quantities with more than two alleles. Thus for populations with multiple biallelic loci, the language of entropy suffices. Then entropy, combined across loci, serves as a concise description of genetic variation. We used individual based simulations to explore how this entropy behaves under different evolutionary scenarios. In agreement with predictions, the entropy associated with unlinked neutral loci decreases over time. However, deviations from free recombination and neutrality have clear and informative effects on the entropy’s behaviour over time.Analysis of publicly available data of a natural D. melanogaster population, that had been sampled over seven years, using a sliding-window approach, yielded considerable variation in entropy trajectories of different genomic regions. These mostly follow a pattern that suggests a substantial effective population size and a limited effect of positive selection on genome-wide diversity over short time scales.

Phase envelopes in reservoir fill analysis: Two contrasting scenarios

Phase envelopes are routinely employed by reservoir engineers for fluid characterisation. These envelopes are controlled by reservoir fluid composition, pressure and temperature. As a result of increasing source-rock maturation, fluids with decreasing molecular weights and densities and increasing gas-to-oil ratios (and hence different phase envelopes) are generated, which are thus linked to fluid history. In addition to their importance for exploration, charge models can play a key role in constraining reservoir models and optimising field development, particularly when pressure–volume-temperature (PVT) data are properly integrated with fluid geochemistry. Two contrasting scenarios of fluid phase evolution from two different fields are presented, and their relations to charge analysis and reservoir models are discussed. The first example discusses the identification, based on hydrocarbon geochemistry complemented by overlapping modeled phase envelopes, of compartmentalised filling cycles in what was initially considered a single oil-rimmed gas accumulation. The second example presents an opposite scenario where two wet gas accumulations 20-km apart laterally and 400-feet average depth difference appear to represent a single more-expansive accumulation spread over areas of variable PVT conditions and reservoir qualities. The wet gas across both accumulations is characterised by a continuous phase evolution pattern that shrinks systematically (cricondentherm shifts to lower temperature and cricondenbar to lower pressure), suggestive of phase fractionation of a charge of single maturity. The proposed gas distribution model represents a discovery of a hybrid conventional and unconventional (tight sand) system, with potential for basin-centered gas. These findings provided better understanding of observed and projected fluids, impacting the development and completion plans by locating new gas producers. A recent well drilled midway between the two accumulations indeed tested wet gas, confirming fluid connectivity. Future work will attempt to link the gas distribution model with seismic attributes.

Dynamical influence of a central massive object on double-barred galaxies: self-destruction mechanism of secondary bars

Abstract Double-barred galaxies exhibit sub-kiloparsec secondary stellar bars that are crucial for channeling gases towards a central massive object (CMO) such as a supermassive black hole or a nuclear star cluster. Recent N-body simulations have uncovered a novel galaxy evolution scenario wherein the mass of the CMO increases owing to the secondary bar, resulting in the eventual destruction of the latter. Consequently, the CMO mass growth halts, thus suggesting a maximum CMO mass of ≈10−3 of the stellar mass of the galaxy. This study focuses on backbone orbit families, particularly double-frequency orbits, within double-barred galaxies. Consequently, the dynamic influence of a CMO on these orbits is investigated. The results of the study reveal the emergence of a new orbital resonance within the central region of the galaxy upon the introduction of a CMO. Orbits subjected to this resonance become chaotic and fail to support the secondary bar, ultimately resulting in the destruction of the entire structure. This is partly because of the inability of the secondary bar to obtain support from the newly generated orbit families following the appearance of resonance. Through the estimation of the condition of secondary bar destruction in realistic double-bar galaxies with varying pattern speeds, the results of the study establish that such destruction occurred when the CMO mass reached ≈10−3 of the galaxy mass. Furthermore, a physical explanation of the galaxy evolution scenario is provided, thereby elucidating the interaction between the CMO and the secondary bar. The understanding of the co-evolution of the secondary bar and the CMO, based on stellar orbital motion, is a crucial step towards future observational studies of stars within the bulge of the Milky Way.

Frequency downshifting in decaying wavetrains on the ocean surface covered by ice floes

We study analytically and numerically a frequency downshifting due to power-type frequency-dependent decay of surface waves in the ocean covered by ice floes. The downshifting is obtained both within the linear model and within the nonlinear Schrödinger (NLS) equation augmented by viscous terms for the initial condition in the form of an NLS envelope soliton. It is shown that the frequency-dependent dissipation produces a more substantial downshifting when the spectrum is relatively wide. As a result, the nonlinear adiabatic scenario of wavetrain evolution provides a downshifting remarkably smaller in magnitude than in the linear regime. Meanwhile, interactions between nonlinear wavegroups lead to spectral broadening and, thus, result in fast substantial frequency downshifts. Analytic estimates are obtained for an arbitrary power n of the dependence of a dissipation rate on frequency ∼ωn. The developed theory is validated by the numerical modeling of the generalized NLS equation with dissipative terms. Estimates of frequency downshift are given for oceanic waves of realistic parameters.

Mata Ni Pachedi: Tales of the goddess on textiles from Gujrat, India

India is a land of vibrant culture and heritage. It is home to many diversified craft techniques, most of which have been intensely investigated, recorded, diversified and revived, while a few have languished. This work reflects the origins and process of the Indian craft Mata Ni Pachedi, which means ‘behind the mother goddess’ and is a cloth that constitutes a temple of the goddess. The original creator of Mata Ni Pachedi is the nomadic Vaghari community from Gujarat, the members of which lived along the banks of the Sabarmati River and worshipped the mother goddess in all her forms. The community created these textiles as an ode to the goddess, as sacred wall art pieces that enabled them to worship the goddess when they could not enter temples due to their low caste. Mata Ni Pachedi is a unique textile that has survived modern-day clothing techniques using natural dyes and simple block printing techniques, exploring different forms of gods and goddesses on cloth. Those in the rural community of Gujrat still worship their goddess on a piece of fabric during the festival of Navratri, in March and September. This research aims to investigate and catalogue the evolution, consumption pattern, production process and present-day scenario of the Mata Ni Pachedi craft to aid and sustain its survival and establish its context in contemporary times.

Parental brain through time: The origin and development of the neural circuit of mammalian parenting.

This review consolidates current knowledge on mammalian parental care, focusing on its neural mechanisms, evolutionary origins, and derivatives. Neurobiological studies have identified specific neurons in the medial preoptic area as crucial for parental care. Unexpectedly, these neurons are characterized by the expression of molecules signaling satiety, such as calcitonin receptor and BRS3, and overlap with neurons involved in the reproductive behaviors of males but not females. A synthesis of comparative ecology and paleontology suggests an evolutionary scenario for mammalian parental care, possibly stemming from male-biased guarding of offspring in basal vertebrates. The terrestrial transition of tetrapods led to prolonged egg retention in females and the emergence of amniotes, skewing care toward females. The nocturnal adaptation of Mesozoic mammalian ancestors reinforced maternal care for lactation and thermal regulation via endothermy, potentially introducing metabolic gate control in parenting neurons. The established maternal care may have served as the precursor for paternal and cooperative care in mammals and also fostered the development of group living, which may have further contributed to the emergence of empathy and altruism. These evolution-informed working hypotheses require empirical validation, yet they offer promising avenues to investigate the neural underpinnings of mammalian social behaviors.

A New Route to Massive Hot Subdwarfs: Common Envelope Ejection from Asymptotic Giant Branch Stars

The hot subdwarf O/B stars (sdO/Bs) are known as extreme horizontal branch stars, which is of great importance in stellar evolution theory. The sdO/Bs are generally thought to have a helium-burning core and a thin hydrogen envelope (M env < 0.02 M ⊙). In the canonical binary evolution scenario, sdO/Bs are considered to be the stripped cores of red giants. However, such a scenario cannot explain the recently discovered sdO/B binary SMSS J1920, where the strong Ca H and K lines in the spectrum are found. It suggests that this binary likely originated from the recent ejection of the common envelope (CE). In this work, we propose a new formation channel of massive sdO/Bs, namely, sdO/Bs produced from a CE ejection process with an asymptotic giant branch (AGB) star (hereafter the AGB CE channel). We constructed the evolutionary model of sdO/Bs and successfully explained most of the important observed parameters of the sdO/B star in SMSS J1920, including the evolutionary age, sdO/B mass, effective temperature, surface gravity, and surface helium abundance. The minimum sdO/B mass produced from the AGB CE channel is about 0.48 M ⊙. The evolutionary tracks in the logTeff–logg plane may explain a fraction of the observational samples with high logTeff and low logg . Considering the wind mass loss of sdO/Bs, the model could produce helium-rich hot subdwarfs with log(nHe/nH)≳−1 .

A Triple Scenario for the Formation of Wide Black Hole Binaries Such as Gaia BH1

Recently, several noninteracting black hole–stellar binaries have been identified in Gaia data—for example, Gaia BH1, where a Sun-like star is in a moderately eccentric (e = 0.44) 185 days orbit around a black hole. This orbit is difficult to explain through binary evolution. The present-day separation suggests the progenitor system would have undergone an episode of common-envelope evolution, but a common envelope should shrink the period below the observed one. Since the majority of massive stars form in higher-multiplicity systems, a triple evolution scenario is more likely for the progenitors of BH binaries. Here we show that such systems can indeed be more easily explained via evolution in hierarchical triple systems. von Zeipel–Lidov–Kozai oscillations or instabilities can delay the onset of the common-envelope phase in the inner binary of the triple, so that the black hole progenitor and low-mass star are more widely separated when it begins, leading to the formation of wider binaries. There are also systems with similar periods but larger eccentricities, where the BH progenitor is a merger product of the inner binary in the triple. Such mergers lead to a more top-heavy black hole mass function.

French grassroots volunteer organizations and prospective: Challenges and avenues for nonprofit research

AbstractThis article explores the importance of prospective for practitioners in the sector of grassroots volunteer organizations (GVOs, as associations). Prospective can be defined as an attitude of studying the future that must lead to action. In this, in times of crisis, prospective seems crucial and the GVOs' point of view can open a research agenda. The French case of GVOs deserves more attention because of their characteristics (e.g., 90% of GVOs have no employees, 75% of them have an annual budget of less than 10,000 euros), their relationship with the public authorities and their strong social impact on the community. The scenarios of evolution of the GVOs sector proposed by La Fonda are analyzed and become filters for the reading of the French literature dedicated to GVOs. They lead to four lines of research (isomorphism; normalization and standardization; evaluation and impact; organizational capacities). Following this, a research agenda dedicated to French GVOs is proposed. This work has intrinsic implications, conducting a literature review and proposing a research agenda compared to international agendas. It highlights the challenges GVOs face and the differences between desirable research in France and international research agendas. It constitutes possible inspirations for GVOs leaders thanks to a synoptic table.

Phylogenetic analyses of the subfamily Scarabaeinae (Coleoptera: Scarabaeidae) provide new insights into the Mexican Transition Zone theory.

Being areas of biotic overlap located between biogeographic regions, transition zones function as natural laboratories. The present study explores the phylogenetic history of the dung beetle subfamily Scarabaeinae, in order to present an evolutionary scenario that allows inference of the biogeographic history of the Mexican Transition Zone (MTZ) and integration of the distributional patterns of its biota. The species sampling included 94 New World taxa (93 species of Scarabaeinae and one species of Aphodiinae). The phylogenetic relationships of the main clades recovered in our study were supported with PP values 0.95. Based on the BAYAREALIKE model to reconstruct the ancestral distributional patterns of Scarabaeinae, we inferred a complex scenario with 19 dispersal events, 15 vicariance events, and three extinctions. We suggest that the Ancient Neotropical and Tropical Paleoamerican patterns represent the most likely ancestral distributional patterns for the Scarabaeinae of the MTZ, which probably settle there during the Eocene-Oligocene. The rest of the Scarabaeinae distributional patterns were assembled in subsequent periods. The results suggest that the MTZ had two separate formation stages: a Paleo-MTZ (Eocene-Miocene) and a current MTZ (Pliocene-Anthropocene). We conclude that the evolutionary history as well as the dispersal-vicariance scenario for the Scarabaeinae of the MTZ fits the out of the tropics model.

Can graphene fuel a transformative change in energy storage technologies? A scenario analysis for the next two decades

In this article, we explore the transformative potential of graphene in electrochemical energy technologies over the next two decades. Using a two-round Delphi survey and 28 expert interviews, we construct three distinct evolutionary scenarios: 1) Current state: graphene has made notable technical advancements, but its transformative potential is limited to “nice-to-have” functionalities, 2) Projected state: graphene's technical progress and adoption of “nice-to-have” functions in energy storage devices will continue, suggesting a gradual evolution, 3) Ideal state: graphene's technical barriers are surmounted, and its transformative capacities are unleashed. Our study's findings challenge the prevailing consensus, which suggests that graphene will have a transformative impact in the near term. Instead, we highlight the complex balance between “nice-to-have” functionalities and genuine transformative capacities. Additionally, we underscore the persistent technical, strategic, and systemic challenges that could shape graphene's trajectory. Finally, we provide an in-depth, analytical assessment and practical implications for both the potential of graphene in energy storage devices and broader innovation generalization dynamics.

Linking Acrosome Size and Genetic Divergence in an Inter-Oceanic Mussel from the Pacific and Atlantic Coasts: A Case of Incipient Speciation?

In recent years, advances in analyses of the sperm morphology and genetics of Perumytilus purpuratus have allowed to two evolutionary scenarios for this mussel to be suggested: (1) the scenario of cryptic species and (2) the scenario of incipient or in progress speciation. For a better understanding of the evolutionary history of P. purpuratus, we performed extensive sampling along a latitudinal gradient of ca. 7180 km of coastline-from the Southern Pacific Ocean to the Atlantic Ocean-and we delved deeper into the sperm morphology of P. purpuratus, exploring its association with the phylogeny and population genetics to determine whether the variability in sperm traits between the northern and southern regions was a signal of cryptic or incipient species. Overall, our results showed that sperm sizes were strongly correlated with the genetic structure in males of P. purpuratus. We identified at 37° S on the Pacific coast a coincident break of both sperm size and genetic disruption that can be explained by historical events and postglacial recolonization as causal phenomena for the observed divergences. Furthermore, evidence of genetic admixture between lineages was found at 38° S, suggesting the presence of an introgressive hybridization zone and incomplete reproductive isolation in an in fraganti or incipient speciation process.

Diversity, origin, and evolution of the ESCRT systems.

Endosomal sorting complexes required for transport (ESCRT) play key roles in protein sorting between membrane-bounded compartments of eukaryotic cells. Homologs of many ESCRT components are identifiable in various groups of archaea, especially in Asgardarchaeota, the archaeal phylum that is currently considered to include the closest relatives of eukaryotes, but not in bacteria. We performed a comprehensive search for ESCRT protein homologs in archaea and reconstructed ESCRT evolution using the phylogenetic tree of Vps4 ATPase (ESCRT IV) as a scaffold and using sensitive protein sequence analysis and comparison of structural models to identify previously unknown ESCRT proteins. Several distinct groups of ESCRT systems in archaea outside of Asgard were identified, including proteins structurally similar to ESCRT-I and ESCRT-II, and several other domains involved in protein sorting in eukaryotes, suggesting an early origin of these components. Additionally, distant homologs of CdvA proteins were identified in Thermoproteales which are likely components of the uncharacterized cell division system in these archaea. We propose an evolutionary scenario for the origin of eukaryotic and Asgard ESCRT complexes from ancestral building blocks, namely, the Vps4 ATPase, ESCRT-III components, wH (winged helix-turn-helix fold) and possibly also coiled-coil, and Vps28-like domains. The last archaeal common ancestor likely encompassed a complex ESCRT system that was involved in protein sorting. Subsequent evolution involved either simplification, as in the TACK superphylum, where ESCRT was co-opted for cell division, or complexification as in Asgardarchaeota. In Asgardarchaeota, the connection between ESCRT and the ubiquitin system that was previously considered a eukaryotic signature was already established.IMPORTANCEAll eukaryotic cells possess complex intracellular membrane organization. Endosomal sorting complexes required for transport (ESCRT) play a central role in membrane remodeling which is essential for cellular functionality in eukaryotes. Recently, it has been shown that Asgard archaea, the archaeal phylum that includes the closest known relatives of eukaryotes, encode homologs of many components of the ESCRT systems. We employed protein sequence and structure comparisons to reconstruct the evolution of ESCRT systems in archaea and identified several previously unknown homologs of ESCRT subunits, some of which can be predicted to participate in cell division. The results of this reconstruction indicate that the last archaeal common ancestor already encoded a complex ESCRT system that was involved in protein sorting. In Asgard archaea, ESCRT systems evolved toward greater complexity, and in particular, the connection between ESCRT and the ubiquitin system that was previously considered a eukaryotic signature was established.

Genomic characterisation and dissection of the onset of resistance to acetyl CoA carboxylase-inhibiting herbicides in a large collection of Digitaria insularis from Brazil.

An in-depth genotypic characterisation of a diverse collection of Digitaria insularis was undertaken to explore the neutral genetic variation across the natural expansion range of this weed species in Brazil. With the exception of Minas Gerais, populations from all other states showed high estimates of expected heterozygosity (HE > 0.60) and genetic diversity. There was a lack of population structure based on geographic origin and a low population differentiation between populations across the landscape as evidenced by average Fst value of 0.02. On combining haloxyfop [acetyl CoA carboxylase (ACCase)-inhibiting herbicide] efficacy data with neutral genetic variation, we found evidence of presence of two scenarios of resistance evolution in this weed species. Whilst populations originating from north-eastern region demonstrated an active role of gene flow, populations from the mid-western region displayed multiple, independent resistance evolution as the major evolutionary mechanism. A target-site mutation (Trp2027Cys) in the ACCase gene, observed in less than 1% of resistant populations, could not explain the reduced sensitivity of 15% of the populations to haloxyfop. The genetic architecture of resistance to ACCase-inhibiting herbicides was dissected using a genome wide association study (GWAS) approach. GWAS revealed association of three SNPs with reduced sensitivity to haloxyfop and clethodim. In silico analysis of these SNPs revealed important non-target site genes belonging to families involved in herbicide detoxification, including UDPGT91C1 and GT2, and genes involved in vacuolar sequestration-based degradation pathway. Exploration of five genomic prediction models revealed that the highest prediction power (≥0.80) was achieved with the models Bayes A and RKHS, incorporating SNPs with additive effects and epistatic interactions, respectively.