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15,277 results for “GENETICS”
Data from: Genetic growth potential, rather than phenotypic size, predicts migration phenotype in Atlantic salmon
<p>Knowledge of the relative importance of genetic versus environmental determinants of major developmental transitions is pertinent to understanding phenotypic evolution. In salmonid fishes, a major developmental transition enables a risky seaward migration that provides access to feed resources. In Atlantic salmon, initiation of the migrant phenotype, and thus age of migrants, is presumably controlled via thresholds of a quantitative liability, approximated by body size expressed long before the migration. However, how well size approximates liability, both genetically and environmentally, remains uncertain. We studied 32 Atlantic salmon families in two temperatures and feeding regimes (fully fed, temporarily restricted) to completion of migration status at age 1 year. We detected a lower migrant probability in the cold (0.42) than the warm environment (0.76), but no effects of male maturation status or feed restriction. By contrast, body length in late summer predicted migrant probability and its control reduced migrant probability heritability by 50–70%. Furthermore, migrant probability and length showed high heritabilities and between-environment genetic correlations, and were phenotypically highly correlated with stronger genetic than environmental contributions. Altogether, quantitative estimates for the genetic and environmental effects predicting the migrant phenotype indicate, for a given temperature, a larger importance of genetic than environmental size effects.</p>
Data from: Multi-scale spatial genetic structure within and between populations of wild cherry trees in nuclear genotypes and chloroplast haplotypes
Spatial genetic structure (SGS) of plants mainly depends on the effective population size and gene dispersal. Maternally inherited loci are expected to have higher genetic differentiation between populations and more intensive SGS within populations than biparentally inherited loci because of smaller effective population sizes and fewer opportunities of gene dispersal in the maternally inherited loci. We investigated biparentally inherited nuclear genotypes and maternally inherited chloroplast haplotypes of microsatellites in 17 tree populations of three wild cherry species under different conditions of tree distribution and seed dispersal. As expected, inter-population genetic differentiation was 6–9 times higher in chloroplast haplotypes than in nuclear genotypes. This difference indicated that pollen flow 4–7 times exceeded seed flow between populations. However, no difference between nuclear and chloroplast loci was detected in within-population SGS intensity due to their substantial variation among the populations. The SGS intensity tended to increase as trees became more aggregated, suggesting that tree aggregation biased pollen and seed dispersal distances toward shorter. The loss of effective seed dispersers, Asian black bears, did not affect the SGS intensity probably because of mitigation of the bear loss by other vertebrate dispersers and too few tree generations after the bear loss to alter SGS. The findings suggest that SGS is more variable in smaller spatial scales due to various ecological factors in local populations.
Data from: The genetic architecture of plant defense tradeoffs in a common monkeyflower
<p>Determining how adaptive combinations of traits arose requires understanding the prevalence and scope of genetic constraints. Frequently observed phenotypic correlations between plant growth, defenses, and/or reproductive timing have led researchers to suggest that pleiotropy or strong genetic linkage between variants affecting independent traits is pervasive. Alternatively, these correlations could arise via independent mutations in different genes for each trait and extensive correlational selection. Here we evaluate these alternatives by conducting a QTL mapping experiment involving a cross between two populations of common monkeyflower (<em>Mimulus guttatus</em>) that differ in growth rate as well as total concentration and arsenal composition of plant defense compounds, phenylpropanoid glycosides (PPGs). We find no evidence that pleiotropy underlies correlations between defense and growth rate. However, there is a strong genetic correlation between levels of total PPGs and flowering time that is largely attributable to a single shared QTL. While this result suggests a role for pleiotropy/close linkage, several other QTLs also contribute to variation in total PPGs. Additionally, divergent PPG arsenals are influenced by a number of smaller-effect QTLs that each underlie variation in one or two PPGs. This result indicates that chemical defense arsenals can be finely-adapted to biotic environments despite sharing a common biochemical precursor. Together, our results show correlations between defense and life history traits are influenced by pleiotropy or genetic linkage, but genetic constraints may have limited impact on future evolutionary responses, as a substantial proportion of variation in each trait is controlled by independent loci.</p>
Rearing environment affects the genetic architecture and plasticity of DNA methylation in Chinook salmon
<p>Genetic architecture and phenotypic plasticity are important considerations when studying trait variation within and among populations. Since environmental change can induce shifts in the genetic architecture and plasticity of traits, it is important to consider both genetic and environmental sources of phenotypic variation. While there is overwhelming evidence for environmental effects on phenotype, the underlying mechanisms are less clear. Variation in DNA methylation is a potential mechanism mediating environmental effects on phenotype due to its sensitivity to environmental stimuli, transgenerational inheritance, and influences on transcription. To characterize the effect of environment on methylation, we created two 6x6 (North Carolina II) Chinook salmon breeding crosses and reared the offspring in two environments: uniform hatchery tanks and semi-natural stream channels. We sampled the fish twice during development, at the alevin (larval) and fry (juvenile) stages. We measured DNA methylation at 13 genes using a PCR-based bisulfite sequencing protocol. The genetic architecture of DNA methylation differed between rearing environments, with greater additive and non-additive genetic variance in hatchery fish and greater maternal effects in semi-natural channel fish, though gene-specific variation was evident. We observed plasticity in methylation across all assayed genes, as well as gene-specific effects at two genes in alevin and six genes in fry, indicating developmental stage-specific effects of rearing environment on methylation. Characterizing genetic and environmental influences on methylation is critical for future studies on DNA methylation as a potential mechanism for acclimation and adaptation.</p>
Low levels of genetic differentiation with isolation by geography and environment in populations of Drosophila melanogaster from across China
<p>The fruit fly <i>Drosophila</i> <i>melanogaster</i> is a model species in evolutionary studies. However, the population processes of this species in East Asia are poorly studied, even though this area was one of the first regions colonized outside of its native distribution range. Here we examined the population genetic structure of <i>D.</i> <i>melanogaster</i> across China. There were 14 mitochondrial haplotypes with ten unique ones out of 23 known from around the globe. Pairwise F<sub>ST</sub> values estimated from 15 novel microsatellites ranged from 0 to 0.11, with geographically isolated populations showing the highest level of genetic uniqueness. STRUCTURE analysis identified high levels of admixture at both the individual and population levels. Mantel tests indicated a strong association between genetic distance and geographical distance as well as environmental distance. Full RDA analysis showed that independent effects of environmental conditions and geography accounted for 62.10% and 31.58% of the total explained genetic variance, respectively. When geographic variables were constrained in a partial RDA analysis, three environmental variables of bio2 (mean diurnal air temperature range), bio13 (precipitation of the wettest month), and bio15 (precipitation seasonality) were correlated with genetic distance. Our study suggests that a high level of gene flow, geographical isolation, and environmental factors have together shaped the population genetic structure of <i>D.</i> <i>melanogaster</i> after its introduction into China.</p>
Loss of ecologically important genetic variation in late generation hybrids reveals links between adaptation and speciation
Adaptation to contrasting environments occurs when advantageous alleles accumulate in each population, but it remains largely unknown whether these same advantageous alleles create genetic incompatibilities that can cause intrinsic reproductive isolation leading to speciation. Identifying alleles that underlie both adaptation and reproductive isolation is further complicated by factors such as dominance and genetic interactions among loci, which can affect both processes differently and obscure potential links between adaptation and speciation. Here, we use a combination of field and glasshouse experiments to explore the connection between adaptation and speciation while accounting for dominance and genetic interactions. We created a hybrid population with equal contributions from four contrasting ecotypes of Senecio lautus (Asteraceae), which produced hybrid genomes both before (F1 hybrid generation) and after (F4 hybrid generation) recombination among the parental ecotypes. In the glasshouse, plants in the second generation (F2 hybrid generation) showed reduced fitness as a loss of fertility, but fertility was recovered in subsequent generations suggesting that genetic variation underlying fertility reduction was lost in subsequent generations. To quantify the effects of losing genetic variation at the F2 generation on the fitness of later generation hybrids, we used a reciprocal transplant to test for fitness differences between parental ecotypes, and F1 and F4 hybrids in all four parental habitats. Compared to the parental ecotypes and F1 hybrids, variance in F4 hybrid fitness was lower, and lowest in habitats that showed stronger native-ecotype advantage, suggesting that stronger natural selection for the native ecotype reduced fitness variation in the F4 hybrids. Fitness trade-offs that were present in the parental ecotypes and F1 hybrids were absent in the F4 hybrid. Together, these results suggest that the genetic variation lost after the F2 generation was likely associated with both adaptation and intrinsic reproductive isolation among populations adapted to contrasting environments.
Genetic algorithm-based personalized models of human cardiac action potential
<p>We present a novel modification of genetic algorithm (GA) which determines personalized parameters of cardiomyocyte electrophysiology model based on set of experimental human action potential (AP) recorded at different heart rates. In order to find the steady state solution, the optimized algorithm performs simultaneous search in the parametric and slow variables spaces. We demonstrate that several GA modifications are required for effective convergence. Firstly, we used a mutation operator, based on Cauchy amplitude distribution along with a random direction in the parametric space. Secondly, relatively large number of elite organisms (6-10 % of the population passed on to new generation) was required for effective convergence. Test runs with synthetic AP as input data indicate that algorithm error is low for high amplitude ionic currents (1.6±1.6% for IKr, 3.2±3.5% for IK1, 3.9±3.5% for INa, 8.2±6.3% for ICaL). Experimental signal-to-noise ratio above 28 dB was required for high quality GA performance. GA was validated against optical mapping recordings of human ventricular AP and mRNA expression profile of donor hearts. In particular, GA output parameters were rescaled proportionally to mRNA levels ratio between patients. We have demonstrated that mRNA-based models predict the AP waveform dependence on heart rate with high precision. The latter also provides a novel technique of model personalization that makes it possible to map gene expression profile to cardiac function. </p>
The roles of climate, geography and natural selection as drivers of genetic and phenotypic differentiation in a widespread amphibian Hyla annectans (Anura: Hylidae)
The role of geological events and Pleistocene climatic fluctuations as drivers of current patterns of genetic variation in extant species has been a topic of continued interest among evolutionary biologists. Nevertheless, comprehensive studies of widely distributed species are still rare, especially from Asia. Using geographically extensive sampling of many individuals and a large number of nuclear single nucleotide polymorphisms (SNPs), we studied the phylogeography and historical demography of Hyla annectans populations in southern China. Thirty-five sampled populations were grouped into seven clearly defined genetic clusters that closely match phenotype-based subspecies classification. These lineages diverged 2.32–5.23 million years ago, a timing that closely aligns with the rapid and drastic uplifting of the Qinghai-Tibet Plateau and adjacent southwest China. Demographic analyses and species distribution models indicate that different populations of this species have responded differently to past climatic changes. In the Hengduan Mountains, most populations experienced a bottleneck, whereas the populations located outside of the Hengduan Mountains have gradually declined in size since the end of the last glaciation. In addition, the levels of phenotypic and genetic divergence were strongly correlated across major clades. These results highlight the combined effects of geological events and past climatic fluctuations, as well as natural selection, as drivers of contemporary patterns of genetic and phenotypic variation in a widely distributed anuran in Asia.
Data from: Curation: heat stress responses and population genetics of the kelp Laminaria digitata (Phaeophyceae) across latitudes reveal differentiation among North Atlantic populations
<p>We aim to understand the thermal plasticity of a coastal foundation species across its latitudinal distribution by assessing physiological responses to high temperature stress in the kelp <i>Laminaria digitata</i> in combination with population genetic characteristics. We <a>hypothesize</a> that Arctic and cold-temperate populations are less heat resilient than warm-temperate populations. Using meristems of natural <i>L. digitata</i> populations from six locations ranging between Kongsfjorden, Spitsbergen (79°N), and Quiberon, France (47°N), we performed a common-garden heat stress experiment applying 15°C to 23°C over eight days. We assessed growth, quantum yield, carbon and nitrogen storage, and xanthophyll pigment contents as response traits. Population connectivity and genetic diversity were analysed with microsatellite markers to relate heat resilience to genetic features and phylogeography. Microsatellite genotyping revealed all sampled populations to be genetically distinct, underlying strong hierarchical structuring between and within southern and northern clades. Genetic diversity was lowest in the isolated population of the North Sea island of Helgoland and highest in Roscoff in the English Channel. Results from the heat stress experiment suggest that the upper temperature limit of <i>L. digitata</i> is nearly identical across its distribution range, but subtle differences we<a>re </a>revealed for the two populations currently at their warm limits. They respectively <a>show</a> a significant advantage in growth at 19°C and 21°C (Quiberon) and a lack of stress responses in photosynthetic quantum yield and xanthophyll pigments at 23°C (Helgoland). In addition, quantum yield indicated the highest heat sensitivity in <i>L. digitata</i> from the northernmost population in Spitsbergen. All together, these results support the hypothesis of moderate local differentiation across <i>L. digitata</i>'s European distribution, whereas effects are likely too weak to ameliorate the species' capacity to withstand ocean warming and marine heatwaves at the southern range edge.</p>
Multiple genetic trajectories to extreme abiotic stress adaptation in Arctic Brassicaceae
<p>Extreme environments offer powerful opportunities to study how different organisms have adapted to similar selection pressures at the molecular level. The Arctic is one of the most hostile environments on Earth, and the few plant species inhabiting this region typically possess suites of similar morphological and physiological adaptations to extremes in light and temperature. Here we compare patterns of molecular evolution in three Brassicaceae species that have independently colonized the Arctic, and present some of the first genetic evidence for plant adaptations to the Arctic environment. By testing for positive selection and identifying convergent substitutions in orthologous gene alignments for a total of 15 Brassicaceae species, we find that positive selection has been acting on different genes, but similar functional pathways in the three Arctic lineages. The positively selected gene sets identified in the three Arctic species showed convergent functional profiles associated with extreme abiotic stress characteristic of the Arctic. However, there was little evidence for independently fixed mutations at the same sites and for positive selection acting on the same genes. The three species appear to have evolved similar suites of adaptations by modifying different components in similar stress response pathways, implying that there could be many genetic trajectories for adaptation to the Arctic environment. By identifying candidate genes and functional pathways potentially involved in Arctic adaptation, our results provide a framework for future studies aimed at testing for the existence of a functional syndrome of Arctic adaptation in the Brassicaceae and perhaps flowering plants in general. </p>
Data from: Dissecting the genetic architecture of a stepwise infection process
How a host fights infection depends on an ordered sequence of steps, beginning with attempts to prevent a pathogen from establishing an infection, through to steps that mitigate a pathogen's control of host resources, or minimising the damage caused during infection. Yet empirically characterising the genetic basis of these steps remains challenging. Although each step is likely to have a unique genetic and environmental signature, and may, therefore, respond to selection in a specific way, events that occur earlier in the infection process can mask or overwhelm the contributions of subsequent steps. In this study, we dissect the genetic architecture of a stepwise infection process using a quantitative trait loci (QTL) mapping approach. We control for variation at the first line of defence against a bacterial pathogen and expose downstream genetic variability related to the host's ability to mitigate the damage pathogens cause. In our model, the water-flea Daphnia magna, we found a single major effect QTL, explaining 64% variance, that is linked to the host's ability to completely block pathogen entry by preventing their attachment to the host oesophagus; consistent with the detection of this locus in prior studies. In susceptible hosts allowing attachment, however, a further 23 QTL, explaining between 5 to 16% variance, were mapped to traits related to the expression of disease. The general lack of pleiotropy and epistasis for traits related to the different stages of the infection process, together with the wide distribution of QTL across the genome, highlights the modular nature of a host's defence portfolio, and the potential for each different step to evolve independently. We discuss how isolating the genetic basis of individual steps can help resolve discussion over the genetic architecture of host resistance.
Breaking ecological barriers: anthropogenic disturbance leads to habitat transitions, hybridization, and high genetic diversity
<p>Genetic diversity is expected to erode in disturbed habitats through strong selection, local extinctions, and recolonization associated with genetic bottlenecks and restricted gene flow. Despite this general prediction and over three decades of population genetics studies, our understanding of the long-term effect of environmental disturbance on local and regional genetic diversity remains limited. We conducted a population genetic survey of the microcrustacean <i>Daphnia</i> across a landscape subject to anthropogenic stressors from a century of industrial mining. At the local scale we found moderate genetic diversity (i.e., low clonal diversity), characteristic of habitat-specific selective sweeps and local extinctions, but high diversity and strong genetic structure at the regional scale despite the shared watershed of many lakes and exceptional dispersal ability of daphniids. Many habitats experienced changes in species assemblages, with the obligate asexual <i>Daphnia pulex</i> lineages—known only to inhabit ponds—dominating disrupted urban lakes. This habitat transition (pond to lake) was likely facilitated by the disruption of ecological barriers maintaining the genomic separation of these young species. Thus, disrupted habitats can exhibit complex and unexpected genetic patterns of local extinctions and recolonizations, followed by habitat transitions, hybridization and potential speciation events that are difficult to predict and should not be underestimated.</p>
Inferred genetic architecture underlying evolution in a fossil stickleback lineage
<p>Inferring the genetic architecture of evolution in the fossil record is difficult because genetic crosses are impossible, the acquisition of DNA is usually impossible, and phenotype-genotype maps are rarely obvious. However, such inference is valuable because it reveals the genetic basis of microevolutionary change across many more generations than is possible in studies of extant taxa, thereby integrating microevolutionary process and macroevolutionary pattern. Here, we infer the genetic basis of pelvic skeleton reduction in <i>Gasterosteus doryssus</i>, a Miocene stickleback fish from a finely resolved stratigraphic sequence that spans nearly 17,000 years. Reduction in pelvic score, a categorical measure of pelvic structure, resulted primarily from reciprocal frequency changes of two discrete phenotypic classes. Pelvic vestiges also showed left-side-larger asymmetry. These patterns implicate <i>Pitx1</i>, a large-effect gene whose deletion generates left-larger asymmetry of pelvic vestiges in extant, closely-related <i>Gasterosteus aculeatus. </i>In contrast, reductions in lengths of the pelvic girdle and pelvic spines resulted from directional shifts of unimodal, continuous trait distributions, suggesting an additional suite of genes with minor, additive pelvic effects, again like <i>G. aculeatus</i>. Similar genetic architectures explain shared but phyletically independent patterns across 10 million years of stickleback evolution.</p>
Chromonomer: a tool set for repairing and enhancing assembled genomes through integration of genetic maps and conserved synteny
<p class="BodyAA">The pace of the sequencing and computational assembly of novel reference genomes is accelerating. Though DNA sequencing technologies and assembly software tools continue to improve, biological features of genomes such as repetitive sequence as well as molecular artifacts that often accompany sequencing library preparation can lead to fragmented or chimeric assemblies. If left uncorrected, defects like these trammel progress on understanding genome structure and function, or worse, positively mislead this research. Fortunately, integration of additional, independent streams of information, such as a marker-dense genetic map and conserved orthologous gene order from related taxa, can be used to scaffold together unlinked, disordered fragments and to restructure a reference genome where it is incorrectly joined. We present a tool set for automating these processes, one that additionally tracks any changes to the assembly and to the genetic map, and which allows the user to scrutinize these changes with the help of web-based, graphical visualizations. Chromonomer takes a user-defined reference genome, a map of genetic markers, and, optionally, conserved synteny information to construct an improved reference genome of chromosome models: a "chromonome". We demonstrate Chromonomer's performance on genome assemblies and genetic maps that have disparate characteristics and levels of quality.</p>
Data from: Disentangling the effects of geographic peripherality and habitat suitability on neutral and adaptive genetic variation in Swiss stone pine
<p><span><span><span><span><span><span><span><span><span><span><span>It is generally accepted that the spatial distribution of neutral genetic diversity within a species' native range mostly depends on effective population size, demographic history, and geographic position. However, it is unclear how genetic diversity at adaptive loci correlates with geographic peripherality or with habitat suitability within the ecological niche. Using exome-wide genomic data and distribution maps of the Alpine range, we first tested whether geographic peripherality correlates with four measures of population genetic diversity at >17,000 SNP loci in 24 Alpine populations (480 individuals) of Swiss stone pine (<i>Pinus cembra</i>) from Switzerland. To distinguish between neutral and adaptive SNP sets, we used four approaches (two gene diversity estimates, <i>F</i><sub>ST</sub> outlier test, and environmental association analysis) that search for signatures of selection. Second, we established ecological niche models for <i>P. cembra</i> in the study range and investigated how habitat suitability correlates with genetic diversity at neutral and adaptive loci. All estimates of neutral genetic diversity decreased with geographic peripherality, but were uncorrelated with habitat suitability. However, heterozygosity (<i>H</i><sub>e</sub>) at adaptive loci based on Tajima's <i>D</i> declined significantly with increasingly suitable conditions. No other diversity estimates at adaptive loci were correlated with habitat suitability. Our findings suggest that populations at the edge of a species' geographic distribution harbour limited neutral genetic diversity due to demographic properties. Moreover, we argue that populations from suitable habitats went through strong selection processes, are thus well adapted to local conditions, and therefore exhibit reduced genetic diversity at adaptive loci compared to populations at niche margins.</span></span></span></span></span></span></span></span></span></span></span></p>
The influence of human genetic variation on Epstein-Barr virus sequence diversity
<p>This project is the first attempt to apply a "genome-to-genome" approach to investigate the impact of the host genetic pressure on the genome of a member of the <em>Herpesviridae</em> family. Namely, 285 pairs of human and EBV genomes were sequenced and multiple GWASes between human and EBV variations were performed. This repository contains the results of downstream analysis on the pathogen-side. The variant calling data was produced from read alignment using BWA mem using GATK HC, SNVer, VarScan2, BCFtools, freebayes and the intersection of the sets of variation from the first three.</p> <ul> <li><strong>The "covstats" files</strong> contains statistics about the read alignment.</li> <li><strong>The tarball SHCS_EBV_variant_call.tar.gz</strong> contains all compressed VCF files.</li> <li><strong>The tarball SHCS_EBV_variant_matrices_stats.tar.gz</strong> contains all matrices used as traits in the GWASes, as well as a variety of statistics.</li> </ul> <p>The pipeline used to generate this data is publically available here: <a href="https://gitlab.com/ezlab/vir_var_calling/">https://gitlab.com/ezlab/vir_var_calling/</a></p>
Data from: No consistent effects of humans on animal genetic diversity worldwide
Human impacts on genetic diversity are poorly understood yet critical to biodiversity conservation. We used 175,247 COI sequences collected between 1980 and 2016 to assess the global effects of land use and human density on the intraspecific genetic diversity of 17,082 species of birds, fishes, insects, and mammals. Human impacts on mtDNA diversity were taxon and scale-dependent, and were generally weak or non-significant. Spatial analyses identified weak latitudinal diversity gradients as well as negative effects of human density on insect diversity, and negative effects of intensive land use on fish diversity. The observed effects were predominantly associated with species turnover. Time series analyses found nearly an equal number of positive and negative temporal trends in diversity, resulting in no net monotonic trend in diversity over this time period. Our analyses reveal critical data and theory gaps and call for increased efforts to monitor global genetic diversity.
Data from: Landscape genetics reveals unique and shared effects of urbanization for two sympatric pool-breeding amphibians
Metapopulation-structured species can be negatively affected when landscape fragmentation impairs connectivity. We investigated the effects of urbanization on genetic diversity and gene flow for two sympatric amphibian species, spotted salamanders (Ambystoma maculatum) and wood frogs (Lithobates sylvaticus), across a large (>35,000 km2) landscape in Maine, USA, containing numerous natural and anthropogenic gradients. Isolation by distance (IBD) patterns differed between the species. Spotted salamanders showed a linear and relatively high variance relationship between genetic and geographic distance (r = 0.057; p < 0.001); whereas, wood frogs exhibited a strongly non-linear and lower variance relationship (r = 0.429; p < 0.001). Scale dependence analysis of IBD found gene flow has its most predictable influence (strongest IBD correlations) at distances up to 9 km for spotted salamanders and up to 6 km for wood frogs. Estimated effective migration surfaces revealed contrasting patterns of high and low genetic diversity and gene flow between the two species. Population isolation, quantified as the mean IBD residuals for each population, was associated with local urbanization and less genetic diversity in both species. The influence of geographic proximity and urbanization on population connectivity was further supported by distance-based redundancy analysis and multiple matrix regression with randomization. Resistance surface modelling found interpopulation connectivity to be influenced by developed land cover, light roads, interstates, and topography for both species, plus secondary roads and rivers for wood frogs. Our results highlight the influence of anthropogenic landscape features within the context of natural features and broad spatial genetic patterns, in turn supporting the premise that while urbanization significantly restricts interpopulation connectivity for wood frogs and spotted salamanders, specific landscape elements have unique effects on these two sympatric species.
Data from: Genome duplication effects on functional traits and fitness are genetic context and species dependent: studies of synthetic polyploid Fragaria
PREMISE OF THE STUDY Divergence in functional traits and adaptive responses to environmental change underlies the ecological advantage of polyploid plants in the wild. While established polyploids may benefit from combined outcomes of genome doubling, hybridization and polyploidy-enabled adaptive evolution, it remains less clear whether genome doubling alone can drive ecological divergence or whether the outcome is genetically variable.METHODS Using synthetic, colchicine-induced, autotetraploid (4x) plants derived from self-pollinated diploid (2x) seeds, and their colchicine-treated but unconverted diploid (2x.nc) full sibs from two diploid wild strawberry taxa (Fragaria vesca ssp. vesca and F. vesca ssp. bracteata), we examined the effects of genome doubling on functional traits, heat stress tolerance and fitness components across taxa and maternal families (i.e. genetic families) within taxa.KEY RESULTS Comparisons between 2x and 2x.nc plants indicated a negligible effect of colchicine treatment on functional traits. Genome doubling increased stomatal length, and decreased stomatal density, specific leaf area and leaf vein density, recapitulating patterns observed in wild polyploid Fragaria. Trichome density, heat stress tolerance and relative growth rate were not significantly affected by genome doubling. Although a reduction in clonal reproduction was observed in response to genome doubling, this effect was strongly genetic family dependent.CONCLUSIONS The results suggest that genome doubling during incipient speciation alone can generate ecological divergence and variation among genetic lineages. This response potentially allows for rapid short-term evolutionary adaptation and fuels genomic diversity and independent origins of polyploidy.
Data from: Cropland connectivity affects genetic divergence of Colorado potato beetle along an invasion front
<p>The population genetic structure of invasive species can be strongly affected by environmental and landscape barriers to dispersal. Disentangling the relative contributions of these factors to genetic divergence among invading populations is a fundamental goal of landscape genetics with important implications for invasion management. Here, we relate patterns of genetic divergence in a global invasive agricultural pest, Colorado potato beetle (CPB; Leptinotarsa decemlineata), to environmental and landscape factors along an invasion front in Northwestern China. We first used microsatellite markers and spatial-temporal samples to assess broad patterns of genetic diversity as well as fine-scale changes in patterns of genetic divergence. We then distinguished the relative contributions of five factors to genetic divergence among front populations: geographic distance (isolation by distance), climate dissimilarity (isolation by environment), and least-cost distances (isolation by resistance) modelled with three factors: climate suitability, cropland cover, and road networks. Genetic diversity broadly decreased from West to East, with the exception being Eastern China. Low levels of genetic diversity and varying degrees of divergence were observed in Northwestern China, reflecting the potential effect of landscape heterogeneity. Least-cost distance across cropland cover was most positively correlated with genetic divergence, suggesting a role of croplands in facilitating gene flow. The contribution of climate to genetic divergence was secondary, whether modelled in terms of local adaptability or connectivity of the climatic landscape, suggesting that constraints to CPB gene flow imposed by a harsh climate may be ameliorated in agricultural landscapes. No evidence was found for an obvious effect of road networks on genetic divergence and population structuring. Our study provides an example of how agricultural landscape connectivity can facilitate the spread of invasive pests, even across a broad climatic gradient. More broadly, our findings can guide decisions about future land management for mitigating further spread.</p>
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.