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The genetic architecture of phenotypic traits can affect the mode and tempo of trait evolution. Human-altered environments can impose strong natural selection, where successful evolutionary adaptation requires swift and large phenotypic shifts. In these scenarios, theory predicts that adaptation is due to a few adaptive variants of large effect, but empirical studies that have revealed the genetic architecture of rapidly evolved phenotypes are rare, especially for populations inhabiting polluted environments. Fundulus killifish have repeatedly evolved adaptive resistance to extreme pollution in urban estuaries. Prior studies, including genome scans for signatures of natural selection, have revealed some of the genes and pathways important for evolved pollution resistance, and provide context for the genotype-phenotype association studies reported here. We created multiple quantitative trait locus (QTL) mapping families using progenitors from four different resistant populations, and using RAD-seq genetically mapped variation in sensitivity (developmental perturbations) following embryonic exposure to a model toxicant PCB-126. We found that one to two large-effect QTL loci accounted for resistance to PCB-mediated developmental toxicity. QTLs harbored candidate genes that govern the regulation of aryl hydrocarbon receptor (AHR) signaling. One QTL locus was shared across all populations and another was shared across three populations. One QTL locus showed strong signatures of recent natural selection in the corresponding wild population but another QTL locus did not. Some candidate genes for PCB resistance inferred from genome scans in wild populations were identified as QTL, but some key candidate genes were not. We conclude that rapidly evolved resistance to the developmental defects normally caused by PCB-126 is governed by few genes of large effect. However, other aspects of resistance beyond developmental phenotypes may be governed by additional loci, such that comprehensive resistance to PCB-126, and to the mixtures of chemicals that distinguish urban estuaries more broadly, may be more genetically complex.
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A core challenge for ecological risk assessment is to integrate molecular responses into a chain of causality to organismal or population-level outcomes. Bioenergetic theory may be a useful approach for integrating suborganismal responses to predict organismal responses that influence population dynamics. We describe a novel application of dynamic energy budget (DEB) theory in the context of a toxicity framework (adverse outcome pathways [AOPs]) to make quantitative predictions of chemical exposures to individuals, starting from suborganismal data. We use early-life stage exposure of Fundulus heteroclitus to dioxin-like chemicals (DLCs) and connect AOP key events to DEB processes through "damage" that is produced at a rate proportional to the internal toxicant concentration. We use transcriptomic data of fish embryos exposed to DLCs to translate molecular indicators of damage into changes in DEB parameters (damage increases somatic maintenance costs) and DEB models to predict sublethal and lethal effects on young fish. By changing a small subset of model parameters, we predict the evolved tolerance to DLCs in some wild F. heteroclitus populations, a data set not used in model parameterization. The differences in model parameters point to reduced sensitivity and altered damage repair dynamics as contributing to this evolved resistance. Our methodology has potential extrapolation to untested chemicals of ecological concern. Environ Toxicol Chem 2023;42:2040-2053. © 2023 Oak Ridge National Laboratory and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Rotas de Resultados Adversos , Dioxinas , Fundulidae , Dibenzodioxinas Policloradas , Animais , Dioxinas/toxicidade , Fundulidae/fisiologia , Dibenzodioxinas Policloradas/toxicidade , Metabolismo EnergéticoRESUMO
The genetic architecture of phenotypic traits can affect the mode and tempo of trait evolution. Human-altered environments can impose strong natural selection, where successful evolutionary adaptation requires swift and large phenotypic shifts. In these scenarios, theory predicts the influence of few adaptive variants of large effect, but empirical studies that have revealed the genetic architecture of rapidly evolved phenotypes are rare, especially for populations inhabiting polluted environments. Fundulus killifish have repeatedly evolved adaptive resistance to extreme pollution in urban estuaries. Prior studies, including genome scans for signatures of natural selection, have revealed some of the genes and pathways important for evolved pollution resistance, and provide context for the genotype-phenotype association studies reported here. We created multiple quantitative trait locus (QTL) mapping families using progenitors from four different resistant populations, and genetically mapped variation in sensitivity (developmental perturbations) following embryonic exposure to a model toxicant PCB-126. We found that a few large-effect QTL loci accounted for resistance to PCB-mediated developmental toxicity. QTLs harbored candidate genes that govern the regulation of aryl hydrocarbon receptor (AHR) signaling, where some (but not all) of these QTL loci were shared across all populations, and some (but not all) of these loci showed signatures of recent natural selection in the corresponding wild population. Some strong candidate genes for PCB resistance inferred from genome scans in wild populations were identified as QTL, but some key candidate genes were not. We conclude that rapidly evolved resistance to the developmental defects normally caused by PCB-126 is governed by few genes of large effect. However, other aspects of resistance beyond developmental phenotypes may be governed by additional loci, such that comprehensive resistance to PCB-126, and to the mixtures of chemicals that distinguish urban estuaries more broadly, may be more genetically complex.
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Selection along environmental gradients can drive reproductive isolation and speciation. Among fishes, salinity is a major factor limiting species distributions, and despite its importance in generating species diversity, speciation events between marine and freshwater are rare. Here, we tested for mechanisms of reproductive isolation between locally adapted freshwater and brackish water-native populations of killifish, Fundulus heteroclitus, from either side of a hybrid zone along a salinity gradient. There was evidence for pre-zygotic endogenous reproductive isolation with reduced fertilization success between crosses of freshwater-native males and brackish water-native females. Exogenous pre-zygotic isolation was also present where females had highest fertilization in their native salinity. We used a replicated mass spawning design to test for mate choice in both brackish and fresh water. After genotyping 187 parents and 2523 offspring at 2347 SNPs across the genome, 85% of offspring were successfully assign to their parents. However, no reinforcing mate choice was observed. These results therefore demonstrate emerging, yet limited, reproductive isolation and incipient speciation across a marine to freshwater salinity gradient and suggest that both endogenous and exogenous mechanisms, but not assortative mating, contribute to divergence.
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Fundulidae , Animais , Feminino , Masculino , Fundulidae/genética , Salinidade , Adaptação Fisiológica , Isolamento Reprodutivo , Água DoceRESUMO
Red abalone, Haliotis rufescens, are herbivorous marine gastropods that primarily feed on kelp. They are the largest and longest-lived of abalone species with a range distribution in North America from central Oregon, United States, to Baja California, MEX. Recently, red abalone have been in decline as a consequence of overharvesting, disease, and climate change, resulting in the closure of the commercial fishery in the 1990s and the recreational fishery in 2018. Protecting this ecologically and economically important species requires an understanding of their current population dynamics and connectivity. Here, we present a new red abalone reference genome as part of the California Conservation Genomics Project (CCGP). Following the CCGP genome strategy, we used Pacific Biosciences HiFi long reads and Dovetail Omni-C data to generate a scaffold-level assembly. The assembly comprises 616 scaffolds for a total size of 1.3 Gb, a scaffold N50 of 45.7 Mb, and a BUSCO complete score of 97.3%. This genome represents a significant improvement over a previous assembly and will serve as a powerful tool for investigating seascape genomic diversity, local adaptation to temperature and ocean acidification, and informing management strategies.
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Gastrópodes , Água do Mar , Animais , México , Concentração de Íons de Hidrogênio , Gastrópodes/genética , GenômicaRESUMO
Ecological transitions across salinity boundaries have led to some of the most important diversification events in the animal kingdom, especially among fishes. Adaptations accompanying such transitions include changes in morphology, diet, whole-organism performance, and osmoregulatory function, which may be particularly prominent since divergent salinity regimes make opposing demands on systems that maintain ion and water balance. Research in the last decade has focused on the genetic targets underlying such adaptations, most notably by comparing populations of species that are distributed across salinity boundaries. Here, we synthesize research on the targets of natural selection using whole-genome approaches, with a particular emphasis on the osmoregulatory system. Given the complex, integrated and polygenic nature of this system, we expected that signatures of natural selection would span numerous genes across functional levels of osmoregulation, especially salinity sensing, hormonal control, and cellular ion exchange mechanisms. We find support for this prediction: genes coding for V-type, Ca2+, and Na+/K+-ATPases, which are key cellular ion exchange enzymes, are especially common targets of selection in species from six orders of fishes. This indicates that while polygenic selection contributes to adaptation across salinity boundaries, changes in ATPase enzymes may be of particular importance in supporting such transitions.
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Osmorregulação , Salinidade , Aclimatação/fisiologia , Animais , Peixes/fisiologia , Brânquias , Osmorregulação/genética , Seleção Genética , ATPase Trocadora de Sódio-Potássio/genética , ATPase Trocadora de Sódio-Potássio/metabolismoRESUMO
RATIONALE, AIMS AND OBJECTIVES: The primary aim of the study was to understand the mindset of doctors and pharmacists, as they embark upon prescribing in a multimorbidity and polypharmacy context during routine practice at a hospital acute admissions unit. The study also aimed to evaluate to what extent attitudes, embedded within real-life decision-making scenarios, relate to existing theory and models of prescribing decisions. METHODS: Anonymized case studies were identified from the medical notes of patients aged 65 and over with conditions likely to be associated with multimorbidity, medication issues and polypharmacy: namely: fall, urinary tract infection, confusion or lower respiratory tract infection. A total of 39 doctors based on the acute medical admissions unit and 9 pharmacists were recruited to one of three focus groups. Patient case-studies provided the context for discussion from which verbatim transcripts were thematically analyzed using an interpretative, qualitative approach. Sub-themes were matched to Murshid and Mohaidin's proposed model of physician prescribing decisions. RESULTS: Seven principal themes were identified that were associated with prescribing decisions on the acute medical unit, namely, "patient characteristics," "drug characteristics," "pharmacist factors," "trustworthiness," "reliability of medication history," "competing priorities" and "responsibilities of prescribers." CONCLUSION: Prescribing decisions on the acute medical admissions unit were influenced by a variety of factors, some of which have already been acknowledged within existing theories and models. The findings provisionally offer new insights, which, subject to confirmation by further research, bring to light three attitudinal characteristics that may impact negatively upon the quality of prescribing decisions. These include, first, how perceived poor reliability of medication history may result in information gaps that compromise prescribing decisions; second, how competing priorities restrict doctors' aptitude to conduct a review of medication and finally, how doctors may rationalize the assignment of medication review to the GP.
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Multimorbidade , Polimedicação , Prescrições de Medicamentos , Humanos , Prescrição Inadequada , Farmacêuticos , Pesquisa Qualitativa , Reprodutibilidade dos TestesRESUMO
The terrestrial radiation of vertebrates required changes in skin that resolved the dual demands of maintaining a mechanical and physiological barrier while also facilitating ion and gas transport. Using the amphibious killifish Kryptolebias marmoratus, we found that transcriptional regulation of skin morphogenesis was quickly activated upon air exposure (1â h). Rapid regulation of cell-cell adhesion complexes and pathways that regulate stratum corneum formation was consistent with barrier function and mechanical reinforcement. Unique blood vessel architecture and regulation of angiogenesis likely supported cutaneous respiration. Differences in ionoregulatory transcripts and ionocyte morphology were correlated with differences in salinity acclimation and resilience to air exposure. Evolutionary analyses reinforced the adaptive importance of these mechanisms. We conclude that rapid plasticity of barrier, respiratory and ionoregulatory functions in skin evolved to support the amphibious lifestyle of K. marmoratus; similar processes may have facilitated the terrestrial radiation of other contemporary and ancient fishes.
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Ciprinodontiformes , Peixes Listrados , Animais , Genômica , Pele , ÁguaRESUMO
Ocean acidification (OA) poses a major threat to marine ecosystems and shellfish aquaculture. A promising mitigation strategy is the identification and breeding of shellfish varieties exhibiting resilience to acidification stress. We experimentally compared the effects of OA on two populations of red abalone (Haliotis rufescens), a marine mollusc important to fisheries and global aquaculture. Results from our experiments simulating captive aquaculture conditions demonstrated that abalone sourced from a strong upwelling region were tolerant of ongoing OA, whereas a captive-raised population sourced from a region of weaker upwelling exhibited significant mortality and vulnerability to OA. This difference was linked to population-specific variation in the maternal provisioning of lipids to offspring, with a positive correlation between lipid concentrations and survival under OA. This relationship also persisted in experiments on second-generation animals, and larval lipid consumption rates varied among paternal crosses, which is consistent with the presence of genetic variation for physiological traits relevant for OA survival. Across experimental trials, growth rates differed among family lineages, and the highest mortality under OA occurred in the fastest growing crosses. Identifying traits that convey resilience to OA is critical to the continued success of abalone and other shellfish production, and these mitigation efforts should be incorporated into breeding programs for commercial and restoration aquaculture.
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Aquicultura/métodos , Gastrópodes/crescimento & desenvolvimento , Gastrópodes/metabolismo , Animais , Fenômenos Biológicos , Ecossistema , Metabolismo Energético , Pesqueiros , Gastrópodes/fisiologia , Concentração de Íons de Hidrogênio , Larva , Moluscos/metabolismo , Alimentos Marinhos , Água do Mar/química , Frutos do MarRESUMO
BACKGROUND: Whole-genome sequencing data from wild-caught individuals of closely related North American killifish species (Fundulus xenicus, Fundulus catenatus, Fundulus nottii, and Fundulus olivaceus) were obtained using long-read Oxford Nanopore Technology (ONT) PromethION and short-read Illumina platforms. FINDINGS: Draft de novo reference genome assemblies were generated using a combination of long and short sequencing reads. For each species, the PromethION platform was used to generate 30-45× sequence coverage, and the Illumina platform was used to generate 50-160× sequence coverage. Illumina-only assemblies were fragmented with high numbers of contigs, while ONT-only assemblies were error prone with low BUSCO scores. The highest N50 values, ranging from 0.4 to 2.7 Mb, were from assemblies generated using a combination of short- and long-read data. BUSCO scores were consistently >90% complete using the Eukaryota database. CONCLUSIONS: High-quality genomes can be obtained from a combination of using short-read Illumina data to polish assemblies generated with long-read ONT data. Draft assemblies and raw sequencing data are available for public use. We encourage use and reuse of these data for assembly benchmarking and other analyses.
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Biologia Computacional/métodos , Fundulidae/genética , Genoma , Genômica/métodos , Animais , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
By investigating evolutionary adaptations that change physiological functions, we can enhance our understanding of how organisms work, the importance of physiological traits, and the genes that influence these traits. This approach of investigating the evolution of physiological adaptation has been used with the teleost fish Fundulus heteroclitus and has produced insights into (i) how protein polymorphisms enhance swimming and development; (ii) the role of equilibrium enzymes in modulating metabolic flux; (iii) how variation in DNA sequences and mRNA expression patterns mitigate changes in temperature, pollution, and salinity; and (iv) the importance of nuclear-mitochondrial genome interactions for energy metabolism. Fundulus heteroclitus provides so many examples of adaptive evolution because their local population sizes are large, they have significant standing genetic variation, and they experience large ranges of environmental conditions that enhance the likelihood that adaptive evolution will occur. Thus, F. heteroclitus research takes advantage of evolutionary changes associated with exposure to diverse environments, both across the North American Atlantic coast and within local habitats, to contrast neutral versus adaptive divergence. Based on evolutionary analyses contrasting neutral and adaptive evolution in F. heteroclitus populations, we conclude that adaptive evolution can occur readily and rapidly, at least in part because it depends on large amounts of standing genetic variation among many genes that can alter physiological traits. These observations of polygenic adaptation enhance our understanding of how evolution and physiological adaptation progresses, thus informing both biological and medical scientists about genotype-phenotype relationships. © 2020 American Physiological Society. Compr Physiol 10:637-671, 2020.
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Adaptação Fisiológica/fisiologia , Evolução Biológica , Fundulidae/fisiologia , Animais , Fundulidae/genética , Regulação da Expressão Gênica , Genômica/métodos , Fenótipo , Polimorfismo GenéticoRESUMO
In this brief note written during a global pandemic, we consider some of the important ways this historical moment is altering the religious landscape, aiming our investigative lens at how religious institutions, congregations, and individuals are affected by the social changes produced by COVID-19. This unprecedented time prompts scholars of religion to reflect on how to strategically approach the study of religion in the time of "social distancing," as well as moving forward. Particularly important considerations include developing heuristic, innovative approaches for revealing ongoing changes to religion, as well as how religion continues to structure social life across a wide range of contexts, from the most intimate and personal to the most public and global. Although our note can only be indicative rather than exhaustive, we do suggest that the initial groundwork for reconsiderations might productively focus on several key analytical themes, including: Epidemiology, Ideology, Religious Practice, Religious Organizations and Institutions, as well as Epistemology and Methodology. In offering these considerations as a starting point, we remain aware (and hopeful) that inventive and unanticipated approaches will also emerge.
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Variation in the metabolic costs associated with organismal maintenance may play a key role in determining fitness, and thus these differences among individuals are likely to be subject to natural selection. Although the evolvability of maintenance metabolism depends on its underlying genetic architecture, relatively little is known about the nature of genetic variation that underlies this trait. To address this, we measured variation in routine metabolic rate (MO2routine ), an index of maintenance metabolism, within and among three populations of Atlantic killifish, Fundulus heteroclitus, including a population from a region of genetic admixture between two subspecies. Polygenic association tests among individuals from the admixed population identified 54 single nucleotide polymorphisms (SNPs) that were associated with MO2routine , and these SNPs accounted for 43% of interindividual variation in this trait. However, genetic associations with MO2routine involved different SNPs if females and males were analysed separately, and there was a sex-dependent effect of mitochondrial genotype on variation in routine metabolism. These results imply that there are sex-specific genetic mechanisms, and potential mitonuclear interactions, that underlie variation in MO2routine . Additionally, there was evidence for epistatic interactions between 17% of the possible pairs of trait-associated SNPs, suggesting that epistatic effects on MO2routine are common. These data demonstrate not only that phenotypic variation in this ecologically important trait has a polygenic basis with considerable epistasis among loci, but also that these underlying genetic mechanisms, and particularly the role of mitochondrial genotype, may be sex-specific.
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Metabolismo Basal/genética , Fundulidae/genética , Mitocôndrias/metabolismo , Consumo de Oxigênio/genética , Animais , Metabolismo Basal/fisiologia , Fundulidae/classificação , Fundulidae/metabolismo , Mitocôndrias/genética , Consumo de Oxigênio/fisiologia , Polimorfismo de Nucleotídeo Único/genética , Fatores SexuaisRESUMO
The mitonuclear species concept hypothesizes that incompatibilities between interacting gene products of the nuclear and mitochondrial genomes are a major factor establishing and maintaining species boundaries. However, most of the data available to test this concept come from studies of genetic variation in mitochondrial DNA, and clines in the mitochondrial genome across contact zones can be produced by a variety of forces. Here, we show that using a combination of population genomic analyses of the nuclear and mitochondrial genomes and studies of mitochondrial function can provide insight into the relative roles of neutral processes, adaptive evolution, and mitonuclear incompatibility in establishing and maintaining mitochondrial clines, using Atlantic killifish (Fundulus heteroclitus) as a case study. There is strong evidence for a role of secondary contact following the last glaciation in shaping a steep mitochondrial cline across a contact zone between northern and southern subspecies of killifish, but there is also evidence for a role of adaptive evolution in driving differentiation between the subspecies in a variety of traits from the level of the whole organism to the level of mitochondrial function. In addition, studies are beginning to address the potential for mitonuclear incompatibilities in admixed populations. However, population genomic studies have failed to detect evidence for a strong and pervasive influence of mitonuclear incompatibilities, and we suggest that polygenic selection may be responsible for the complex patterns observed. This case study demonstrates that multiple forces can act together in shaping mitochondrial clines, and illustrates the challenge of disentangling their relative roles.
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Evolução Biológica , Núcleo Celular/fisiologia , Fundulidae/fisiologia , Genoma , Mitocôndrias/fisiologia , Animais , Fundulidae/genética , Especiação Genética , Genoma Mitocondrial , Mitocôndrias/genéticaRESUMO
Killifish (Fundulus heteroclitus) are widely distributed among different aquatic environments where they demonstrate an impressive range of highly-plastic and locally adaptive phenotypes. High-throughput sequencing has begun to unravel the mechanisms and evolutionary history of these interesting features by establishing relationships in the genotype-phenotype map. However, some genotype-phenotype analyses require a higher order of contiguity than what initial scaffolded (fragmented genome assembly where contigs have been assemble into scaffolds) genome assemblies can provide. Here, we used 5,685 high-quality RAD-Seq markers from a single mapping family to order 84% of the scaffolded genome assembly to 24 chromosomes. This serves to: 1) expand the killifish genomic toolkit, 2) estimate genome-wide recombination rates, and 3) compare genome synteny to humans and other fishes. After initially building our map, we found that the selection of thresholds for sequence data filtration highly impacted scaffold placement in the map. We outline each step of the approach that dramatically improved our map to help guide others toward more effective linkage mapping for genome assembly. Our final map supports strong conservation of genomic synteny among closely related fish species and reveals previously described chromosomal rearrangements between more distantly related clades. However, we also commonly found minor scaffold misorientations in F. heteroclitus and in other assemblies, suggesting that further mapping (such as optical mapping) is necessary for finer scale resolution of genome structure. Lastly, we discuss the problems that would be expected from misoriented/unplaced scaffolds and stress the importance of a quality mapped genome as a key feature for further investigating population and comparative genomic questions with F. heteroclitus and other taxa.
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Mapeamento Cromossômico/métodos , Fundulidae/genética , Animais , Feminino , Proteínas de Peixes/genética , Marcadores Genéticos , Genótipo , Masculino , SinteniaRESUMO
Recent research shows that Americans who adhere to Christian nationalism-an ideology that idealizes and advocates a fusion of Christianity and American civic life-tend to hold authoritarian and exclusionary attitudes, particularly regarding ethno-racial minorities and nontraditional family forms. Such findings suggest a fundamental connection between Christian nationalism and rigid symbolic boundaries, which would likely extend to Americans' understanding of gender roles. Drawing on notions connecting religious nationalism with defenses of patriarchal norms and utilizing a recent national, random sample of American adults, the current study examines the link between contemporary Christian nationalism and traditionalist gender ideologies. Our analyses reveal that Christian nationalism is the strongest predictor of holding a more traditionalist gender ideology, even after taking into account a host of political and religious characteristics. Moreover, the relationship between Christian nationalism and gender traditionalism holds across religious traditions, including more gender-egalitarian groups like Mainline Protestants and even the unaffiliated. We conclude by highlighting the implications of these findings for understanding contemporary populist support for Donald Trump, which previous studies have shown is undergirded by both Christian nationalism and sexism.
Des recherches récentes démontrent que les adeptes américains du nationalisme chrétien - idéologie qui promeut de manière idéaliste une fusion du christianisme et de la vie civile américaine - tendent à arborer une attitude autoritaire et sectaire, particulièrement en ce qui a trait aux minorités ethnoraciales et aux organisations familiales non traditionnelles. De telles conclusions suggèrent un rapport fondamental entre le nationalisme chrétien et des bornes symboliques rigides qui s'étendent vraisemblablement à la manière dont les Américains comprennent le rôle des sexes. S'inspirant des notions reliant le nationalisme chrétien à la défense des normes patriarcales et utilisant un échantillon aléatoire récent d'adultes américains, l'étude actuelle examine le lien qui existe entre le nationalisme chrétien actuel et l'idéologie traditionnelle sur les sexes. Nos résultats révèlent que le nationalisme chrétien constitue le plus fort prédicteur de l'adoption d'une idéologie plus traditionnelle sur les sexes, même en tenant compte d'une multitude de facteurs politiques et religieux. Qui plus est, le lien entre nationalisme chrétien et traditionalisme quant au rôle des sexes se retrouve dans toutes les traditions religieuses, y compris des groupes plus égalitaires quant au sexe comme les grandes églises protestantes et même les églises non affiliées. Nous pouvons conclure en soulignant comment s'appliquent ces résultats à la compréhension du soutien populiste actuel dont jouit Donald Trump qui, comme des études précédentes l'ont démontré, est sous-tendu tant par le nationalisme chrétien que par le sexisme.
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Marine wildlife populations are adapted to survive in highly dynamic environments. However, identifying the effects of endogenous versus exogenous variables on marine mammal physiology remains a substantial challenge in part because of the logistical constraints that limit the collection of physiological data in free-ranging animals. Measuring genome-wide gene expression is one minimally invasive method that can be used to elucidate how free-ranging cetaceans' physiological responses shift with changing environmental conditions or demographic states, i.e. reproductive status and maturity. We identified transcriptomic differences among bottlenose dolphins (Tursiops truncatus) from the Southern California Bight using RNAseq data from the skin of 75 individuals to examine gene expression associated with sex, pregnancy status, sea surface temperature, geographic location and ecotype. We identified transcriptomic variation between two genetically distinct ecotypes as well as variation related to environmental conditions among groups that exhibit little evidence of genetic divergence. Specifically, we found differential expression of genes associated with structural development, cellular starvation and immune response. Sex and pregnancy status explained a small proportion of the observed variation, in contrast to sea surface temperature, which explained a substantial amount of transcriptomic variation. However, these measured variables did not account for all of the differential expression observed between ecotypes and among geographically distinct groups. Additional research is needed to identify other endogenous or exogenous factors that may be contributing to observed transcriptomic differences among ecotypes.
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Radical environmental change that provokes population decline can impose constraints on the sources of genetic variation that may enable evolutionary rescue. Adaptive toxicant resistance has rapidly evolved in Gulf killifish (Fundulus grandis) that occupy polluted habitats. We show that resistance scales with pollution level and negatively correlates with inducibility of aryl hydrocarbon receptor (AHR) signaling. Loci with the strongest signatures of recent selection harbor genes regulating AHR signaling. Two of these loci introgressed recently (18 to 34 generations ago) from Atlantic killifish (F. heteroclitus). One introgressed locus contains a deletion in AHR that confers a large adaptive advantage [selection coefficient (s) = 0.8]. Given the limited migration of killifish, recent adaptive introgression was likely mediated by human-assisted transport. We suggest that interspecies connectivity may be an important source of adaptive variation during extreme environmental change.
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Adaptação Biológica/genética , Poluição Ambiental , Evolução Molecular , Fundulidae/genética , População/genética , Receptores de Hidrocarboneto Arílico/genética , Alelos , Migração Animal , Animais , Fluxo Gênico , Variação Genética , Hidrocarbonetos Policíclicos Aromáticos/toxicidadeRESUMO
Cetaceans in the Southern California Bight (SCB) are exposed to high levels of halogenated organic contaminants (HOCs), which have previously been linked to impaired reproductive health and immune responses. We used a combination of molecular tools to examine the potential physiological impacts of HOC exposure in two bottlenose dolphin ( Tursiops truncatus) ecotypes in the SCB. We quantified 25 HOCs in the blubber of 22 biopsies collected from males between 2012 and 2016. We then analyzed genome-wide gene expression in skin using RNA-sequencing and measured blubber testosterone to compare HOC exposure with cellular and endocrine biomarkers. We found high levels of HOCs in both ecotypes with significantly higher total polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), tris(4-chlorophenyl)methanol (TCPMOH), and chlordane-related compounds in the coastal ecotype versus the offshore ecotype. We found evidence of PBDE bioaccumulation in both ecotypes, however, the pattern of bioaccumulation or endocrine disruption for other HOCs was different between the ecotypes, suggesting potential endocrine disruption in the coastal ecotype. We also observed correlations between HOCs and gene coexpression networks enriched for xenobiotic metabolism, hormone metabolism, and immune response that could indicate cellular effects from HOC exposure. By integrating measurements of HOC load with both transcriptome profiling and endocrine biomarkers, our approach provides insight into HOC exposure and potential impacts on wild cetacean health in southern California.
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Golfinho Nariz-de-Garrafa , Bifenilos Policlorados , Poluentes Químicos da Água , Animais , Biomarcadores , California , Monitoramento Ambiental , MasculinoRESUMO
Urban ecosystems are rapidly expanding throughout the world, but how urban growth affects the evolutionary ecology of species living in urban areas remains largely unknown. Urban ecology has advanced our understanding of how the development of cities and towns change environmental conditions and alter ecological processes and patterns. However, despite decades of research in urban ecology, the extent to which urbanization influences evolutionary and eco-evolutionary change has received little attention. The nascent field of urban evolutionary ecology seeks to understand how urbanization affects the evolution of populations, and how those evolutionary changes in turn influence the ecological dynamics of populations, communities, and ecosystems. Following a brief history of this emerging field, this Perspective article provides a research agenda and roadmap for future research aimed at advancing our understanding of the interplay between ecology and evolution of urban-dwelling organisms. We identify six key questions that, if addressed, would significantly increase our understanding of how urbanization influences evolutionary processes. These questions consider how urbanization affects nonadaptive evolution, natural selection, and convergent evolution, in addition to the role of urban environmental heterogeneity on species evolution, and the roles of phenotypic plasticity versus adaptation on species' abundance in cities. Our final question examines the impact of urbanization on evolutionary diversification. For each of these six questions, we suggest avenues for future research that will help advance the field of urban evolutionary ecology. Lastly, we highlight the importance of integrating urban evolutionary ecology into urban planning, conservation practice, pest management, and public engagement.