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502 results for “natural populations”
Data from: Contrasting patterns of divergence at the regulatory and sequence level in European Daphnia galeata natural populations
Understanding the genetic basis of local adaptation has long been the focus of evolutionary biology. Recently there has been increased interest in deciphering the evolutionary role of Daphnia's plasticity and the molecular mechanisms of local adaptation. Using transcriptome data, we assessed the differences in gene expression profiles and sequences within and between four European Daphnia galeata populations. To distinguish neutral from adaptive differentiation, we corrected for phylogenetic differentiation of Daphnia populations. We also applied a "transcriptome scan" approach to investigate the role of natural selection in shaping divergent expression profiles among populations. Furthermore, a SNP analysis allowed inferring population structure and the distribution of genetic variation. Using sequence information, the transcripts were annotated using a comparative genomics approach. In total, ~33% of 32903 transcripts were differentially expressed between populations. Among 10280 differentially expressed transcripts, 5209 transcripts deviated from neutral expectations and were likely involved in local adaptation. The population divergence at the sequence level was higher than at the gene expression level by several orders of magnitude and revealed very distinct clusters according to population origin. Our analysis revealed the respective roles of genetic drift and selection in the four Daphnia populations. This study is a first attempt to understand the genetic background of adaptation to environmental changes in a key species of aquatic ecosystems in absence of any laboratory induced stressor.
Data from: Environmental and genetic influences on body mass and resting metabolic rates (RMR) in a natural population of weasel Mustela nivalis
Body mass (BM) and resting metabolic rates (RMR) are two inexorably linked traits strongly related to mammalian life histories. Yet, there have been no studies attempting to estimate heritable variation and covariation of BM and RMR in natural populations. We used a marker-based approach to construct a pedigree and then the 'animal model' to estimate narrow sense heritability (h^2) of these traits in a free-living population of weasels Mustela nivalis – a small carnivore characterised by a wide range of BM and extremely high RMR. The most important factors affecting BM of weasels were sex and habitat type, whereas RMR was significantly affected only by seasonal variation of this trait. All environmental factors had only small effect on estimates of additive genetic variance of both BM and RMR. The amount of additive genetic variance associated with BM and estimates of heritability were high and significant in males (h^2 = 0.61), but low and not significant in females (h^2 = 0.32), probably due to small sample size for the latter sex. The results from the two-trait model revealed significant phenotypic (r_P = 0.62) and genetic correlation (r_A = 0.89) between BM and whole body RMR. The estimate of heritability of whole body RMR (0.54) and body mass corrected RMR (0.45) were lower than estimates of heritability for BM. Both phenotypic and genetic correlations between body mass corrected RMR and BM had negative signals (r_P = -0.42 and r_A = -0.58). Our results indicate that total energy expenditures of individuals can quickly evolve through concerted changes in BM and RMR.
Data from: Prey exploitation and dispersal strategies vary among natural populations of a predatory mite
When predators commonly overexploit local prey populations, dispersal drives the dynamics in local patches, which together form a metapopulation. Two extremes in a continuum of dispersal strategies are distinguished: the "Killer" strategy, where predators only start dispersing when all prey are eliminated, and the "Milker" strategy, in which predator dispersal occurs irrespective of prey availability. Theory shows that the Milker strategy is not evolutionarily stable if local populations are well connected by dispersal. Using strains of the predatory mite Phytoseiulus persimilis, collected from 11 native populations from coastal areas in Turkey and Sicily, we investigated whether these two strategies occur in nature. In small wind tunnels, we measured dispersal rates and population dynamics of all populations in a system consisting of detached rose leaves, spider mites (Tetranychus urticae) as prey, and P. persimilis. We found significant variation in the exploitation and dispersal strategies among predator populations, but none of the collected strains showed the extreme Killer or Milker strategy. The results suggest that there is genetic variation for prey exploitation and dispersal strategies. Thus, different dispersal strategies in the Milker–Killer continuum may be selected for under natural conditions. This may affect the predator–prey dynamics in local populations and is likely to determine persistence of predator–prey systems at the metapopulation level.
Data from: Conflicting selection on the timing of germination in a natural population of Arabidopsis thaliana
The timing of germination is a key life-history trait that may strongly influence plant fitness and that sets the stage for selection on traits expressed later in the life cycle. In seasonal environments, the period favourable for germination and the total length of the growing season are limited. The optimal timing of germination may therefore be governed by conflicting selection through survival and fecundity. We conducted a field experiment to examine the effects of timing of germination on survival, fecundity and overall fitness in a natural population of the annual herb Arabidopsis thaliana in north-central Sweden. Seedlings were transplanted at three different times in late summer and in autumn covering the period of seed germination in the study population. Early germination was associated with low seedling survival, but also with high survival and fecundity among established plants. The advantages of germinating early more than balanced the disadvantage and selection favoured early germination. The results suggest that low survival among early germinating seeds is the main force opposing the evolution of earlier germination and that the optimal timing of germination should vary in space and time as a function of the direction and strength of selection acting during different life-history stages.
Data from: Climate-related adaptive genetic variation and population structure in natural stands of Norway spruce in the South-Eastern Alps
Forest trees dominate many Alpine landscapes that are currently exposed to changing climate. Norway spruce is one of the most important conifer species of the Italian Alps, and natural populations are found across steep environmental gradients with large differences in temperature and moisture availability. This study seeks to determine and quantify patterns of genetic diversity in natural populations toward understanding adaptive responses to changing climate. Across the Italian species range, 24 natural stands were sampled with a major focus on the Eastern Italian Alps. Sampled trees were genotyped for 384 selected single nucleotide polymorphisms (SNPs) from 285 genes. A wide array of potential candidate genes was tested for correlation with climatic parameters. To minimize false-positive association between genotype and climate, population structure was investigated. Pairwise F ST estimates between sampled populations ranged between 0.000 and 0.075, with the highest values involving the two disjoint populations, Valdieri, on the western Italian Alps, and Campolino, the most southern population on the Apennines. Despite considerable genetic admixture among populations, both Bayesian and multivariate approach identified four genetic clusters. Selection scans revealed five F ST outliers, and the environmental association analysis detected ten SNPs associated to one or more climatic variables. Overall, 13 potentially adaptive loci were identified, three of which have been reported in a previous study on the same species conducted on a broader geographical scale. In our study, precipitation, more than temperature, was often associated with genotype; therefore, it appears as the most important environmental variable associated with the high sensitivity of Norway spruce to soil water supply. These findings provide relevant information for understanding and quantifying climate change effects on this species and its ability to genetically adapt.
Experimental hybridization studies suggest that pleiotropic alleles commonly underlie adaptive divergence between natural populations
<p>The alleles used for adaptation can pleiotropically affect traits under stabilizing selection. The fixation of alleles with deleterious pleiotropic effects causes compensatory alleles to be favoured by selection. Such compensatory alleles might segregate in interpopulation hybrids, resulting in segregation variance for traits where parents have indistinguishable phenotypes. If adaptation typically involves pleiotropy and compensation, then the segregation variance for traits under stabilizing selection is expected to increase with the magnitude of adaptive phenotypic divergence between parents. This prediction has not been tested empirically, and I gathered data from experimental hybridization studies to evaluate it. I found that pairs of parents which are more phenotypically divergent beget hybrids with more segregation variance in traits for which the parents are statistically indistinguishable. This result suggests that adaptive divergence between pairs of natural populations proceeds via pleiotropy and compensation, and that deleterious transgressive segregation variance accumulates systematically as populations diverge.</p>
Data from: Low temperature reveals genetic variability against male-killing Spiroplasma in Drosophila melanogaster natural populations
Spiroplasma endosymbionts are maternally inherited microorganisms which infect many arthropod species. In some Drosophila species, it acts as a reproductive manipulator, spreading in populations by killing the sons of infected mothers. Distinct Drosophila melanogaster populations from Brazil exhibit variable male-killing Spiroplasma prevalences. In this study, we investigated the presence of variability for the male-killing phenotype among Drosophila and/or Spiroplasma strains and verified if it correlates with the endosymbiont prevalence in natural populations. For that, we analyzed the male-killing expression when Spiroplasma strains from different populations were transferred to a standard D. melanogaster line (Canton-S) and when a common Spiroplasma strain was transferred to different wild-caught D. melanogaster lines, both at optimal and challenging temperatures for the bacteria. No variation was observed in the male-killing phenotype induced by different Spiroplasma strains. No phenotypic variability among fly lines was detected at optimal temperature (23 °C), as well. Conversely, significant variation in the male-killing expression was revealed among D. melanogaster lines at 18.5 °C, probably caused by imperfect transmission of the endosymbiont. Distinct lines differed in their average sex ratios as well as in the pattern of male-killing expression as the infected females aged. Greater variation occurred among lines from one locality, although there was no clear correlation between the male-killing intensity and the endosymbiont prevalence in each population. Imperfect transmission or male killing may also occur in the field, thus helping to explain the low or intermediate prevalences reported in nature. We discuss the implications of our results for the dynamics of male-killing Spiroplasma in natural populations.
Data from: Genetic divergence and signatures of natural selection in marginal populations of a keystone, long-lived conifer, eastern white pine (Pinus strobus) from northern Ontario
Marginal populations are expected to provide the frontiers for adaptation, evolution and range shifts of plant species under the anticipated climate change conditions. Marginal populations are predicted to show genetic divergence from central populations due to their isolation, and divergent natural selection and genetic drift operating therein. Marginal populations are also expected to have lower genetic diversity and effective population size (Ne) and higher genetic differentiation than central populations. We tested these hypotheses using eastern white pine (Pinus strobus) as a model for keystone, long-lived widely-distributed plants. All 614 eastern white pine trees, in a complete census of two populations each of marginal old-growth, central old-growth, and central second-growth, were genotyped at 11 microsatellite loci. The central populations had significantly higher allelic and genotypic diversity, latent genetic potential (LGP) and Ne than the marginal populations. However, heterozygosity and fixation index were similar between them. The marginal populations were genetically diverged from the central populations. Model testing suggested predominant north to south gene flow in the study area with curtailed gene flow to northern marginal populations. Signatures of natural selection were detected at three loci in the marginal populations; two showing divergent selection with directional change in allele frequencies, and one balancing selection. Contrary to the general belief, no significant differences were observed in genetic diversity, differentiation, LGP, and Ne between old-growth and second-growth populations. Our study provides information on the dynamics of migration, genetic drift and selection in central versus marginal populations of a keystone long-lived plant species and has broad evolutionary, conservation and adaptation significance.
Data from: Microsatellite genetic structure and cytonuclear discordance in naturally fragmented populations of deer mice (Peromyscus maniculatus)
The Great Lakes impose high levels of natural fragmentation on local populations of terrestrial animals in a way rarely found within continental ecosystems. Although separated by major water barriers, woodland deer mouse (Peromyscus maniculatus gracilis) populations on the islands and on the Upper Peninsula (UP) and Lower Peninsula (LP) of Michigan have previously been shown to have a mitochondrial DNA contact zone that is incongruent with the regional landscape. We analyzed 11 microsatellite loci for 16 populations of P. m. gracilis distributed across 2 peninsulas and 6 islands in northern Michigan to address the relative importance of geographical structure and inferred postglacial colonization patterns in determining the nuclear genetic structure of this species. Results showed relatively high levels of genetic structure for this species and a significant correlation between interpopulation differentiation and separation by water but little genetic structure and no isolation-by-distance within each of the 2 peninsulas. Genetic diversity was generally high on both peninsulas but lower and correlated to island size in the Beaver Island Archipelago. These results are consistent with the genetic and demographic isolation of Lower Peninsula populations, which is a matter of concern given the dramatic decline in P. m. gracilis abundance on the Lower Peninsula in recent years.
Data from: Will natural resistance result in populations of ash trees remaining in British woodlands after a century of ash dieback disease?
Novel pests and diseases are becoming increasingly common, and often cause additional mortality to host species in the newly contacted communities. This can alter the structure of the community up to, and including, the extinction of host species. In the last twenty years, ash dieback disease (ADB) has spread into Europe from East Asia. It has caused substantial mortality in ash tree (Fraxinus excelsior L.) populations. However, a proportion of the individuals in most populations appears to be less susceptible to ADB and resistance seems to have high heritability. These observations have led to suggestions that ash populations may be sustainable after the disease. In order to test this hypothesis, I modified an existing model of UK woodland (parameterised for Wytham Woods, Oxfordshire) to take into account the impact of ADB, and allowed offspring to inherit resistance traits from their parent. The results suggest that ash populations would still exist in 100 years but at lower levels than they are currently. For example, when the initial proportion of resistant individuals is about 10% and heritability of resistance is 0.5, then the population of ash falls to about one third of present levels. The proportion of individuals initially resistant to ADB had a larger effect on population size after 100 years than the heritability of resistance. The fact that the initial size of the resistant population is important to achieving a high population size in the presence of ADB suggests that a selective breeding programme with the intention of augmenting the natural ash populations would be beneficial.
Data from: Functional genomic and phenotypic responses to desiccation in natural populations of a desert drosophilid
We used whole transcriptome microarrays to assess changes in gene expression and monitored mortality rates and epicuticular hydrocarbons (CHCs) in response to desiccation stress in four natural populations of Drosophila mojavensis from Baja California and mainland Mexico. Desiccation had the greatest effect on gene expression, followed by biogeographical variation at regional and population levels. Genes involved in environmental sensing and cuticular structure were up-regulated in dry conditions, while genes involved in transcription itself were down-regulated. Flies from Baja California had higher expression of reproductive and mitochondrial genes, suggesting that these populations have greater fecundity and higher metabolic rates. Host plant differences had a surprisingly minor effect on the transcriptome. In most cases, desiccation-caused mortality was greater in flies reared on fermenting cactus tissues than laboratory media. Water content of adult females and males was significantly different, and was lower in Baja California males. Different groups of CHCs simultaneously increased and decreased in amounts due to desiccation exposure of 9 and 18 hr and were population-specific and dependent on larval rearing substrates. Overall, we observed that changes in gene expression involved a coordinated response of metabolic, behavioral, and cuticular genes. Together with differential expression of cuticular hydrocarbons, this study revealed some of the mechanisms that have allowed D. mojavensis to exploit its harsh desert conditions. Certainly, for D. mojavensis that uses different host plants, population-level understanding of responses to stressors associated with future climate change in desert regions must be evaluated across geographical and local ecological scales.
Data from: Clonality, genetic diversity, and support for the diversifying selection hypothesis, in natural populations of a flower-living yeast
Vast amounts of effort have been devoted to investigate patterns of genetic diversity and structuring in plants and animals, but similar information is scarce for organisms of other kingdoms. The study of the genetic structure of natural populations of wild yeasts can provide insights on the ecological and genetic correlates of clonality, and on the generality of recent hypotheses postulating that microbial populations lack the potential for genetic divergence and allopatric speciation. Ninety-one isolates of the flower-living yeast Metschnikowia gruessii from southeastern Spain were DNA fingerprinted using AFLP markers. Genetic diversity and structuring was investigated with band-based methods and model- and nonmodel-based clustering. Linkage disequilibrium tests were used to assess reproduction mode. Microsite-dependent, diversifying selection was tested by comparing genetic characteristics of isolates from bumble bee vectors and different floral microsites. AFLP polymorphism (91%) and genotypic diversity were very high. Genetic diversity was spatially structured, as shown by AMOVA (Φst = 0.155) and clustering. The null hypothesis of random mating was rejected, clonality seeming the prevailing reproductive mode in the populations studied. Genetic diversity of isolates declined from bumble bee mouthparths to floral microsites, and frequency of five AFLP markers varied significantly across floral microsites, thus supporting the hypothesis of diversifying selection on clonal lineages. Wild populations of clonal fungal microbes can exhibit levels of genetic diversity and spatial structuring that are not singularly different from those shown by sexually reproducing plants or animals. Microsite-dependent, divergent selection can maintain high local and regional genetic diversity in microbial populations despite extensive clonality.
Data from: Dynamic expressions of hypothalamic genes regulate seasonal breeding in a natural rodent population
Seasonal breeding is a universal reproductive strategy in many animals. Hypothalamic genes, especially type 2 and 3 iodothyronine deiodinases (Dio2/3), RFamide-related peptide 3 (Rfrp-3), kisspeptin (Kiss-1), and gonadotropin-releasing hormone (GnRH), are involved in a photoperiodic pathway that encodes seasonal signals from day length in many vertebrate species. However, the seasonal expression patterns of these genes in wild mammals are less studied. Here, we present a four-year field investigation to reveal seasonal rhythm and age-dependent reproductive activity in male Brandt's voles (Lasiopodomys brandtii) and to detect relationships among seasonal expression profiles of hypothalamic genes, testicular activity, age, and annual day length. From breeding season (April) to non-breeding season (October), adult male voles displayed a synchronous peak in gonadal activity with annual day length around summer solstice, which was jointly caused by age structure shifts and age-dependent gonadal development patterns. Overwintered males maintained reproductive activity until late in the breeding season, whereas most newborn males terminated gonadal development completely, except for a minority of males born early in spring. Consistently, the synchronous and opposite expression profiles of Dio2/3 suggest their central function to decode photoperiodic signals and to predict the onset of the non-breeding season. Moreover, changes in Dio2/3 signals may guide the actions of Kiss-1 and Rfrp-3 to regulate the age-dependent divergence of reproductive strategy in wild Brandt's vole. Our results provide evidence on how hypothalamic photoperiod genes regulate seasonal breeding in a natural rodent population.
Data from: Release from natural enemies mitigates inbreeding depression in native and invasive Silene latifolia populations
Inbreeding and enemy infestation are common in plants and can synergistically reduce their performance. This inbreeding × environment (I×E) interaction may be of particular importance for the success of plant invasions if introduced populations experience a release from attack by natural enemies relative to their native conspecifics. Here, we investigate whether inbreeding affects plant infestation damage, whether inbreeding depression in growth and reproduction is mitigated by enemy release and whether this effect is more pronounced in invasive than native plant populations. We used the invader Silene latifolia and its natural enemies as a study system. We performed two generations of experimental out- and inbreeding within eight native (European) and eight invasive (North American) populations under controlled conditions using field-collected seeds. Subsequently, we exposed the offspring to an enemy exclusion and inclusion treatment in a common garden in the species' native range to assess the interactive effects of population origin (range), breeding treatment and enemy treatment on infestation damage, growth and reproduction. Inbreeding increased flower and leaf infestation damage in plants from both ranges, but had opposing effects on fruit damage in native versus invasive plants. Inbreeding significantly reduced plant fitness, whereby inbreeding depression in fruit number was higher in enemy inclusions than exclusions. This effect was equally pronounced in populations from both distribution ranges. Moreover, the magnitude of inbreeding depression in fruit number was lower in invasive than native populations. These results support that inbreeding has the potential to reduce plant defenses in S. latifolia, which magnifies inbreeding depression in the presence of enemies. However, future studies are necessary to further explore whether enemy release in the invaded habitat has actually decreased inbreeding depression and thus facilitated the persistence of inbred founder populations and invasion success. In addition, our findings emphasize the importance of purging for for successful range expansion.
Data from: Temporal genetic stability in natural populations of the waterflea Daphnia magna in response to strong selection pressure
Studies monitoring changes in genetic diversity and composition through time allow a unique understanding of evolutionary dynamics and persistence of natural populations. However, such studies are often limited to species with short generation times that can be propagated in the laboratory or few exceptional cases in the wild. Species that produce dormant stages provide powerful models for the reconstruction of evolutionary dynamics in the natural environment. A remaining open question is to what extent dormant egg banks are an unbiased representation of populations and hence of the species' evolutionary potential, especially in presence of strong environmental selection. We address this key question using the water flea Daphnia magna, which produces dormant stages that accumulate in biological archives over time. We assess temporal genetic stability in three biological archives, previously used in resurrection ecology studies showing adaptive evolutionary responses to rapid environmental change. We show that neutral genetic diversity does not decline with the age of the population and it is maintained in presence of strong selection. In addition, by comparing temporal genetic stability in hatched and unhatched populations from the same biological archive, we show that dormant egg banks can be consulted to obtain a reliable measure of genetic diversity over time, at least in the multi-decadal time frame studied here. The stability of neutral genetic diversity through time is likely mediated by the buffering effect of the resting egg bank.
Data from: Genetic source-sink dynamics among naturally structured and anthropogenically fragmented puma populations
Fragmentation of wildlife populations is increasing on a global scale and understanding current population genetic structure, genetic diversity, and genetic connectivity is key to informing wildlife management and conservation. We genotyped 992 pumas (Puma concolor) at 42 previously developed microsatellite loci and identified 10 genetic populations throughout the states of California and Nevada, USA. Although some genetic populations had large effective population sizes, others were small and inbred. Genetic diversity was extremely variable (heterozygosity, uHe = 0.33–0.53), with some populations nearly as low as an endangered subspecies, the Florida Panther (P. c. coryi, uHe = 0.24). Specifically, pumas in the Sierra Nevada were genetically diverse and formed the largest genetic source population in the region. In contrast, coastal and southern populations surrounded by urbanization had low genetic diversity, fragmented gene flow, and tended to be genetic sinks. The strong population genetic structuring of pumas across California (FST = 0.05–0.39) is vastly different than other genetic studies in less-urbanized states, including our analysis in Nevada, where pumas had few barriers to gene flow and weak population differentiation. Our results have far-reaching conservation and management implications for pumas and indicate large-scale fragmentation in one of North America's most biodiverse and rapidly-urbanizing regions.
Data from: Supportive breeding boosts natural population abundance with minimal negative impacts on fitness of a wild population of Chinook salmon
While supportive breeding programs strive to minimize negative genetic impacts to populations, case studies have found evidence for reduced fitness of artificially produced individuals when they reproduce in the wild. Pedigrees of two complete generations were tracked with molecular markers to investigate differences in reproductive success (RS) of wild and hatchery-reared Chinook salmon spawning in the natural environment to address questions regarding the demographic and genetic impacts of supplementation to a natural population. Results show a demographic boost to the population from supplementation. On average, fish taken into the hatchery produced 4.7 times more adult offspring, and 1.3 times more adult grand-offspring than naturally reproducing fish. Of the wild and hatchery fish that successfully reproduced, we found no significant differences in RS between any comparisons but hatchery-reared males typically had lower RS values than wild males. Mean relative reproductive success (RRS) for hatchery F1 females and males was 1.11 (p = 0.84) and 0.89 (p = 0.56), respectively. RRS of hatchery-reared fish (H) that mated in the wild with either hatchery or wild origin (W) fish were generally equivalent to WxW matings. Mean RRS of HxW and HxH matings was 1.07 (p = 0.92) and 0.94 (p = 0.95), respectively. We conclude that fish chosen for hatchery rearing did not have a detectable negative impact on the fitness of wild fish by mating with them for a single generation. Results suggest that supplementation following similar management practices (e.g., 100% local, wild-origin brood stock) can successfully boost population size with minimal impacts on the fitness of salmon in the wild.
Data from: Wide variation in spatial genetic structure between natural populations of the European beech (Fagus sylvatica) and its implications for SGS comparability
Identification and quantification of spatial genetic structure (SGS) within populations remains a central element of understanding population structure at the local scale. Understanding such structure can inform on aspects of the species' biology, such as establishment patterns and gene dispersal distance, in addition to sampling design for genetic resource management and conservation. However, recent work has identified that variation in factors such as sampling methodology, population characteristics, and marker system can all lead to significant variation in SGS estimates. Consequently, the extent to which estimates of SGS can be relied upon to inform on the biology of a species or differentiate between experimental treatments is open to doubt. Following on from a recent report of unusually extensive SGS when assessed using amplified fragment length polymorphisms (AFLP) in the tree Fagus sylvatica, we explored whether this marker system led to similarly high estimates of SGS extent in other apparently similar populations of this species. In the three populations assessed, SGS extent was even stronger than this previously reported maximum, extending up to 360 m, an increase of up to 800% in comparison with the generally accepted maximum of 30 - 40 m based on the literature. Within this species, wide variation in SGS estimates exists, whether quantified as SGS intensity, extent, or the Sp parameter. Consequently, we argue that greater standardisation should be applied in sample design and SGS estimation and highlight five steps that can be taken to maximize the comparability between SGS estimates.
Data from: Parasitic versus nutritional regulation of natural fish populations
1. Although parasites are expected to affect their host's fitness, quantitative proof for impacts of parasitism on wild populations is hampered by confounding environmental factors, including dietary resource. 2. Herein, we evaluate whether the physiological conditions of European perch (Perca fluviatilis) in three large peri-alpine lakes (Geneva, Annecy, and Bourget) depend on (a) the nutritional status of the juvenile fish, as revealed by stable isotope and fatty acid compositions, (b) the prevalence of the tapeworm Triaenophorus nodulosus, a parasite transmitted to perch through copepod preys, or (c) interactive effects of both factors. 3. At the scale of lake populations, the deficit in growth and fat storage of juvenile perch during their first summer coincides with a high parasite prevalence and also a low quality of dietary resource. 4. Yet, at the individual level, parasites had no evident effect on the growth of the juvenile perch, while impacts on fat storage appeared only at the highest prevalence of the most infected lake. Fatty acid and stable isotope analyses of fish tissue do not reveal any impact of T. nodulosus on diet, physiology, and feeding behaviour of fish within lakes. 5. Overall, we found a low impact of parasitism on the physiological condition and trophic status of juvenile perch at the end of their first summer. We find instead that juvenile perch growth and fat storage, both factors tied to their winter survival, are under strong nutritional constraints. 6. However, the coinciding nutritional constraints and parasite prevalence of perch juveniles in these three lakes may result from the indirect effect of lake nutrient concentrations, which, as a major control of zooplankton communities, simultaneously regulate both the dietary quality of fish prey and the host–parasite encounter rates.
Variation at an adhesin locus suggests sociality in natural populations of the yeast Saccharomyces cerevisiae
<p>Microbes engage in numerous social behaviors that are critical for survival and reproduction, and that require individuals to act as a collective. Various mechanisms ensure that collectives are composed of related, cooperating cells, thus allowing for the evolution and stability of these traits, and for selection to favor traits beneficial to the collective. Since microbes are difficult to observe directly, sociality in natural populations can instead be investigated using evolutionary genetic signatures, as social loci can be evolutionary hotspots. The budding yeast has been studied for over a century, yet little is known about its social behavior in nature. Flo11 is a highly regulated cell adhesin required for most lab social phenotypes; studies suggest it may function in cell recognition and its heterogenous expression may be adaptive for collectives such as biofilms. We investigated this locus and found positive selection in the areas implicated in cell-cell interaction, suggesting selection for kin discrimination. We also found balancing selection at an upstream activation site, suggesting selection on the level of variegated gene expression. Our results suggest this model yeast is surprisingly social in natural environments and is likely engaging in various forms of sociality. By utilizing genomic data, this research provides a glimpse of otherwise unobservable interactions.</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.