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54,099 results for “Expression”
Data from: Impacts of temperature and lunar day on gene expression profiles during a monthly reproductive cycle in the brooding coral Pocillopora damicornis
Reproductive timing in brooding corals has been correlated to temperature and lunar irradiance, but the mechanisms by which corals transduce these environmental variables into molecular signals are unknown. To gain insight into these processes, global gene expression profiles in the coral Pocillopora damicornis were examined (via RNA-Seq) across lunar phases and between temperature treatments, during a monthly planulation cycle. The interaction of temperature and lunar day together had the largest influence on gene expression. Mean timing of planulation, which occurred at lunar days 7.4 and 12.5 for 28- and 23°C-treated corals, respectively, was associated with an upregulation of transcripts in individual temperature treatments. Expression profiles of planulation-associated genes were compared between temperature treatments, revealing that elevated temperatures disrupted expression profiles associated with planulation. Gene functions inferred from homologous matches to online databases suggest complex neuropeptide signalling, with calcium as a central mediator, acting through tyrosine kinase and G protein-coupled receptor pathways. This work contributes to our understanding of coral reproductive physiology and the impacts of environmental variables on coral reproductive pathways.
Data from: Crossing phenotype heritability and candidate gene expression in grafted black-lipped pearl oyster Pinctada margaritifera, an animal chimera
Grafting mantle tissue of a donor pearl oyster into the gonad of a recipient oyster results in the formation of a chimera, the pearl sac. The phenotypic variations of this chimera are hypothesized to be the result of interactions between the donor and recipient genomes. In this study, the heritability of phenotypic variation and its association with gene expression were investigated for the first time during P. margaritifera pearl production. Genetic variance was evaluated at different levels, 1) before the graft operation (expression in graft tissue), 2) after grafting (pearl sac tissue expression in chimera) and 3) on the product of the graft (pearl phenotype traits) based on controlled bi-parental crosses and the F1 generation. Donor related genetic parameter estimates clearly demonstrate heritability for nacre weight and thickness, darkness and colour, surface defects and grade, which signifies a genetic basis in the donor oyster. In graft relative gene expression, the value of heritability was superior to 0.20 in for almost all genes, while in pearl sac, heritability estimates were low (h² < 0.10) (except for CALC1 and Aspein). Pearl sac expression seems to be more influenced by residual variance than the graft, which can be explained by environmental effects that influence pearls sac gene expression and act as a recipient additive genetic component. The interactions between donor and recipient are very complex and further research is required to understand the role of the recipient oysters on pearl phenotypic and gene expression variances.
Data from: Differential gene expression analysis of symbiotic and aposymbiotic Exaiptasia anemones under immune challenge with Vibrio coralliilyticus
Anthozoans are a class of Cnidarians that includes scleractinian corals, anemones and their relatives. Despite a global rise in disease epizootics impacting scleractinian corals, little is known about the immune response of this key group of invertebrates. To better characterize the anthozoan immune response, we used the model anemone Exaiptasia pallida to explore the genetic links between the anthozoan-algal symbioses and immunity in a two-factor RNA-Seq experiment using both symbiotic and aposymbiotic(menthol-bleached) Exaiptasia pallida exposed to the bacterial pathogen Vibrio coralliilyticus. Multivariate and univariate analyses of Exaiptasia gene expression demonstrated that exposure to live Vibrio coralliilyticus had strong and significant impacts on transcriptome-wide gene expression for both symbiotic and aposymbiotic anemones, but we did not observe strong interactions between symbiotic state and Vibrio exposure. There were 4,164 significantly differentially expressed (DE) genes for Vibrio exposure, 1,114 DE genes for aposymbiosis, and 472 DE genes for the additive combinations of Vibrio and aposymbiosis. KEGG enrichment analyses identified 11 pathways - involved in immunity (5), transport and catabolism (4) and cell growth and death (2) - that were enriched due to both Vibrio and/or aposymbiosis. Immune pathways showing strongest differential expression included complement, coagulation, nucleotide-binding and oligomerization domain (NOD), and Toll for Vibrio exposure and coagulation and apoptosis for aposymbiosis.
Data from: Antennal transcriptome analysis and expression profiles of odorant binding proteins in Eogystia hippophaecolus (Lepidoptera: Cossidae)
Background: Eogystia hippophaecolus (Hua et al.) (Lepidoptera: Cossidae) is the major threat to seabuckthorn plantations in China. Specific and highly efficient artificial sex pheromone traps was developed and used to control it. However, the molecular basis for the pheromone recognition is not known. So we established the antennal transcriptome of E. hippophaecolus and characterized the expression profiles of odorant binding proteins. These results establish and improve the basis knowledge of the olfactory receptive system, furthermore provide a theoretical basis for the development of new pest control method. Results: We identified 29 transcripts encoding putative odorant-binding proteins (OBPs), 18 putative chemosensory proteins (CSPs), 63 odorant receptors (ORs), 13 gustatory receptors (GRs), 12 ionotropic receptors (IRs), and two sensory neuron membrane proteins (SNMPs). Based on phylogenetic analysis, we found one Orco and three pheromone receptors of E. hippophaecolus and found that EhipGR13 detects sugar, EhipGR11 and EhipGR3 detect bitter. Nine OBPs expression profile indicated that most were the highest expression in antennae, consistent with functions of OBPs in binding and transporting odors during the antennal recognition process. OBP6 was external expressed in male genital-biased in, and this locus may be responsible for pheromone binding and recognition as well as mating. OBP1 was the highest and biased expressed in the foot and may function as identification of host plant volatiles. Conclusions: One hundred thirty-seven chemosensory proteins were identified and the accurate functions and groups of part proteins were obtained by phylogenetic analysis. The most OBPs were antenna-biased expressed, which are involved in antennal recognition. However, few OBP was detected biased expression in the foot and external genitalia, and these loci may function in pheromone recognition, mating, and the recognition of plant volatiles.
Data from: The evolution of heat shock protein sequences, cis-regulatory elements, and expression profiles in the eusocial Hymenoptera
Background: The eusocial Hymenoptera have radiated across a wide range of thermal environments, exposing them to significant physiological stressors. We reconstructed the evolutionary history of three families of Heat Shock Proteins (Hsp90, Hsp70, Hsp40), the primary molecular chaperones protecting against thermal damage, across 12 Hymenopteran species and four other insect orders. We also predicted and tested for thermal inducibility of eight Hsps from the presence of cis-regulatory heat shock elements (HSEs). We tested whether Hsp induction patterns in ants were associated with different thermal environments. Results: We found evidence for duplications, losses, and cis-regulatory changes in two of the three gene families. One member of the Hsp90 gene family, hsp83, duplicated basally in the Hymenoptera, with shifts in HSE motifs in the novel copy. Both copies were retained in bees, but ants retained only the novel HSE copy. For Hsp70, Hymenoptera lack the primary heat-inducible orthologue from Drosophila melanogaster and instead induce the cognate form, hsc70-4, which also underwent an early duplication. Episodic diversifying selection was detected along the branch predating the duplication of hsc70-4 and continued along one of the paralogue branches after duplication. Four out of eight Hsp genes were heat-inducible and matched the predictions based on presence of conserved HSEs. For the inducible homologues, the more thermally tolerant species, Pogonomyrmex barbatus, had greater Hsp basal expression and induction in response to heat stress than did the less thermally tolerant species, Aphaenogaster picea. Furthermore, there was no trade-off between basal expression and induction. Conclusions: Our results highlight the unique evolutionary history of Hsps in eusocial Hymenoptera, which has been shaped by gains, losses, and changes in cis-regulation. Ants, and most likely other Hymenoptera, utilize lineage-specific heat inducible Hsps, whose expression patterns are associated with adaptive variation in thermal tolerance between two ant species. Collectively, our analyses suggest that Hsp sequence and expression patterns may reflect the forces of selection acting on thermal tolerance in ants and other social Hymenoptera.
Data from: Identifying the critical climatic time window that affects trait expression
Identifying the critical time window during which climatic drivers affect the expression of phenological, behavioral, and demographic traits is crucial for predicting the impact of climate change on trait and population dynamics. Two widely used associative methods exist to identify critical climatic periods: sliding-window models and recursive operators in which the memory of past weather fades over time. Both approaches have different strong points, which we combine here into a single method. Our method uses flexible functions to differentially weight past weather, which can reflect competing hypotheses about time lags and the relative importance of recent and past weather for trait expression. Using a 22-year data set, we illustrate that the climatic window identified by our new method explains more of the phenological variation in a sexually selected trait than existing approaches. Our new method thus helps to better identify the critical time window and the causes of trait response to environmental variability.
Data from: The influence of population structure on gene expression and flowering time variation in the ubiquitous weed Capsella bursa-pastoris (Brassicaceae)
Population structure is a potential problem when testing for adaptive phenotypic differences among populations. The observed phenotypic differences among populations can simply be due to genetic drift, and if the genetic distance between them is not considered, the differentiation may be falsely interpreted as adaptive. Conversely, adaptive and demographic processes might have been tightly associated and correcting for the population structure may lead to false negatives. Here, we evaluated this problem in the cosmopolitan weed Capsella bursa-pastoris. We used RNA-Seq to analyse gene expression differences among 24 accessions, which belonged to a much larger group that had been previously characterized for flowering time and circadian rhythm and were genotyped using genotyping-by-sequencing (GBS) technique. We found that clustering of accessions for gene expression retrieved the same three clusters that were obtained with GBS data previously, namely Europe, the Middle East and Asia. Moreover, the three groups were also differentiated for both flowering time and circadian rhythm variation. Correction for population genetic structure when analysing differential gene expression analysis removed all differences among the three groups. This may suggest that most differences are neutral and simply reflect population history. However, geographical variation in flowering time and circadian rhythm indicated that the distribution of adaptive traits might be confounded by population structure. To bypass this confounding effect, we compared gene expression differentiation between flowering ecotypes within the genetic groups. Among the differentially expressed genes, FLOWERING LOCUS C was the strongest candidate for local adaptation in regulation of flowering time.
Data from: Adaptive differences in gene expression associated with heavy metal tolerance in the soil arthropod Orchesella cincta
Field-selected tolerance to heavy metals has been reported for Orchesella cincta (Arthropoda: Collembola) populations occurring at metal-contaminated mining sites. This tolerance is correlated with heritable increase of metal excretion efficiency; less pronounced cadmium (Cd) induced growth reduction and, over-expression of the metallothionein gene. We applied transcriptomics to determine differential gene expression caused by this abiotic stress in reference and Cd tolerant populations. Many cDNAs responded to Cd exposure in the reference population. Significantly fewer clones were Cd responsive in tolerant animals. Analysis of variance revealed transcripts that interact between Cd exposure and population. Hierarchical cluster analysis of these clones identified two major groups. The first one contained cDNAs that were up regulated by Cd in the reference culture, but non-responsive or down regulated in tolerant animals. This cluster was also characterized by elevated constitutive expression in the tolerant population. Gene ontology analysis revealed that these cDNAs were involved in structural integrity of the cuticle, anti-microbial defense, calcium-channel blocking, sulfur assimilation and chromatin remodeling. The second group consisted of cDNAs down regulated in reference animals but not responding or slightly up regulated in tolerant animals. Their functions involved carbohydrate metabolic processes, Ca2+ dependent stress signaling, redox state, proteolysis and digestion. The reference population showed a strong signature of stress-induced genome-wide perturbation of gene expression, whereas the tolerant animals maintained normal gene expression upon Cd exposure. We confirmed the micro-evolutionary processes occurring in soil arthropod populations and suggest a major contribution of gene regulation to the evolution of a stress-adapted phenotype.
Data from: Differential gene expression in Acromyrmex leaf-cutting ants after challenges with two fungal pathogens
Social insects in general and leaf-cutting ants in particular have increased selection pressures on their innate immune system due to their social lifestyle and monoclonality of the symbiotic fungal cultivar. As this symbiosis is obligate for both parties, prophylactic behavioural defences against infections are expected to increase either ant survival or fungus-garden survival, but also to possibly trade off when specific infections differ in potential danger. We examined the effectiveness of prophylactic behaviours and modulations of innate immune defences by a combination of inoculation bioassays and genome-wide transcriptomic studies (RNA-Seq), using an ant pathogen (Metarhizium brunneum) and a fungus-garden pathogen (Escovopsis weberi) and administering inoculations both directly and indirectly (via the symbiotic partner). Upon detection of pathogen conidia, ant workers responded by increasing both general activity and the frequency of specific defence behaviours (self-grooming, allo-grooming, garden-grooming) independent of the pathogen encountered. This trend was also evident in the patterns of gene expression change. Both direct and indirect (via fungus garden) inoculations with Metarhizium induced a general up-regulation of gene expression, including a number of well-known immune-related genes. In contrast, direct inoculation of the fungus garden by Escovopsis induced an overall down-regulation of ant gene expression, whereas indirect inoculation (via the ants) did not, suggesting that increased activity of ants to remove this fungus-garden pathogen is costly and involves trade-offs with the activation of other physiological pathways.
Differential influence of Slc7a11 expression and body condition on pheomelanin‐based pigmentation in two Eurasian nuthatch Sitta europaea populations with different predation risk
<p><span><span><span><span><span><span><span><span><span><span><span>The expression of the gene <i>Slc7a11</i>promotes the antioxidant capacity of cells by providing them with cysteine that can be used for the synthesis of glutathione (GSH), the most important intracellular antioxidant. In melanocytes, intracellular cysteine can also enter melanosomes and get incorporated in the pigment pheomelanin synthesis pathway, thus decreasing cysteine availability for GSH synthesis and potentially creating chronic oxidative stress. We thus hypothesized that a mechanism limiting the use of intramelanocytic cysteine for pheomelanin synthesis in environmental conditions generating oxidative stress may be physiologically advantageous and favored by natural selection. Here we searched for evidence of such a mechanism by comparing the influence of melanocytic <i>Slc7a11</i>expression on pheomelanin-based pigmentation in developing Eurasian nuthatch <i>Sitta europaea</i>nestlings from two populations differing in predation risk, a natural source of oxidative stress. Pheomelanin synthesis and pigmentation tended to increase with <i>Slc7a11</i>expression in the low-risk population as expected from the activity of this gene, but decreased with <i>Slc7a11</i>expression in the high-risk population. The same was not observed in the expression of five other genes influencing pheomelanin synthesis without affecting cysteine availability in melanocytes. The influence of body condition on the intensity of pheomelanin-based pigmentation also differed between populations, being positive in the low-risk population and negative in the high-risk population. The resulting pigmentation of birds was more intense in the high-risk population. These findings suggest that birds perceiving high predation risk may limit the use of cysteine for pheomelanin synthesis, which becomes independent of <i>Slc7a11</i>expression. Some birds may have thus evolved the ability to adjust their pigmentation phenotype to environmental stress.</span></span></span></span></span></span></span></span></span></span></span></p>
Data from: Impact of microRNA expression in human atrial tissue in patients with atrial fibrillation undergoing cardiac surgery
Background: Although microRNA (miRNA) regulates initiation and/or progression of atrial fibrillation (AF) in canine AF models, the underlying mechanism in humans remains unclear. We speculated that certain miRNAs in atrial tissue are related to AF, and evaluated the relationship of miRNA expression in human atrial tissue in cardiac surgery patients. Methods: Right atrial tissues from 29 patients undergoing cardiovascular surgery were divided into 3 groups [A: chronic AF or unsuccessful maze, n=6; B: successful maze, n=10; C: sinus rhythm (SR) n=13]. miRNA expression was determined using high density microarrays and with Reverse transcriptase-polymerase chain reaction (RT-PCR). Fibrosis was examined using Masson trichrome staining. Results: miRNA microarray analysis showed elevated miRNA-21, miRNA-23b, miRNA-199b, and miRNA-208b in AF as compared to SR groups. RT-PCR showed elevated miRNA-21 (1.9-fold) and miRNA-208b (4.2-fold) in AF as compared to the SR groups. miRNA-21 expression increased from Group C to A (A: 2.1-fold, B: 1.8-fold, C: 1.0-fold). Fibrosis increased from C to A (A: 43.0±12.9%, B: 21.3±6.1%, C: 11.9±3.1%). Percent fibrosis and miRNA-21 expression were correlated (r=0.508, p<0.05). The plasma levels of miRNA-21 in AF patients was significantly decreased as compared to the healthy volunteers (p<0.05). Conclusion: The expression of miRNA-21 in human atrial tissue was found to be related to atrial fibrosis and might affect AF occurrence, indicating its usefulness as a biomarker for cardiac surgery management.
Data from: Among-lake reciprocal transplants induce convergent expression of immune genes in threespine stickleback
Geographic variation in parasite communities can drive evolutionary divergence in host immune genes. However, biotic and abiotic environmental variation can also induce plastic differences in immune function among populations. At present, there is little information concerning the relative magnitudes of heritable vs. induced immune divergence in natural populations. We examined immune gene expression profiles of threespine stickleback (Gasterosteus aculeatus) from six lakes on Vancouver Island, British Columbia. Parasite community composition differs between lake types (large or small, containing limnetic- or benthic-like stickleback) and between watersheds. We observed corresponding differences in immune gene expression profiles among wild-caught stickleback, using a set of seven immune genes representing distinct branches of the immune system. To evaluate the role of environmental effects on this differentiation, we experimentally transplanted wild-caught fish into cages in their native lake, or into a nearby foreign lake. Transplanted individuals' immune gene expression converged on patterns typical of their destination lake, deviating from their native expression profile. Transplant individuals' source population had a much smaller effect, suggesting relatively weak genetic underpinning of population differences in immunity, as viewed through gene expression. This strong environmental regulation of immune gene expression provides a counterpoint to the large emerging literature documenting microevolution and genetic diversification of immune function. Our findings illustrate the value of studying immunity in natural environmental settings where the immune system has evolved and actively functions.
Data from: Heat shock protein expression enhances heat tolerance of reptile and bird embryos
The role of heat shock proteins (HSPs) in heat tolerance has been demonstrated in cultured cells and animal tissues, but rarely in whole organisms because of methodological difficulties associated with gene manipulation. By comparing HSP70 expression patterns among representative species of reptiles and birds, and by determining the effect of HSP70 overexpression on embryonic development and hatchling traits, we have identified the role of HSP70 in the heat tolerance of amniote embryos. Consistent with their thermal environment, and high incubation temperatures and heat tolerance, the embryos of birds have higher onset and maximum temperatures for induced HSP70 than do reptiles, and turtles have higher onset and maximum temperatures than do lizards. Interestingly, the trade-off between benefits and costs of HSP70 overexpression occurred between life-history stages: when turtle embryos developed at extreme high temperatures, HSP70 overexpression generated benefits by enhancing embryo heat tolerance and hatching success, but subsequently imposed costs by decreasing heat tolerance of surviving hatchlings. Taken together, the correlative and causal links between HSP70 and heat tolerance provide, to our knowledge, the first unequivocal evidence that HSP70 promotes thermal tolerance of embryos in oviparous amniotes.
Data from: Reverse genetics in the tidepool: knockdown of target gene expression via RNA interference in the copepod Tigriopus californicus
Reverse genetic tools are essential for characterizing phenotypes of novel genes and testing functional hypotheses generated from next-generation sequencing studies. RNA interference (RNAi) has been a widely used technique for describing or quantifying physiological, developmental or behavioural roles of target genes by suppressing their expression. The marine intertidal copepod Tigriopus californicus has become an emerging model for evolutionary and physiological studies, but this species is not amenable to most genetic manipulation approaches. As crustaceans are susceptible to RNAi-mediated gene knock-down, we developed a simple method for delivery of gene-specific double-stranded RNA that results in significant suppression of target gene transcription levels. The protocol was examined on five genes of interest, and for each, at least 50% knock-down in expression was achieved. While knock-down levels did not reach 100% in any trial, a well-controlled experiment with one heat-shock gene showed unambiguously that such partial gene suppression may cause dramatic changes in phenotype. Copepods with suppressed expression of heat-shock protein beta 1 (hspb1) exhibited dramatically decreased tolerance to high temperatures, validating the importance of this gene during thermal stress, as proposed by a previous study. The application of this RNAi protocol in T. californicus will be invaluable for examining the role of genes putatively involved in reproductive isolation, mitochondrial function and local adaptation.
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: Elovanoids counteract oligomeric β-Amyloid-induced gene expression and protect photoreceptors
<p><span>The onset of neurodegenerative diseases activates inflammation that leads to progressive neuronal cell death and impairments in cognition (Alzheimer's disease, AD) and sight (age-related macular degeneration, AMD). How neuroinflammation can be counteracted is not known. In AMD, amyloid β-peptide (Aβ) accumulates in subretinal drusen. In the 5xFAD retina, we found early functional deficiencies (ERG) without photoreceptor cell (PRC) death and identified early insufficiency in biosynthetic pathways of pro-homeostatic/neuroprotective mediators, neuroprotectin D1 (NPD1) and elovanoids (ELVs). To mimic an inflammatory milieu in wild-type (WT) mouse, we triggered retinal pigment epithelium (RPE) damage/PRC death by subretinally injected oligomeric β-Amyloid (OAβ) and observed that ELVs administration counteracted their effects, protecting these cells. In addition, ELVs prevented OAβ-induced changes in gene expression engaged in senescence, inflammation, autophagy, extracellular matrix remodeling and AMD. Moreover, since OAβ target the RPE, we used primary human RPE cell cultures and demonstrated that OAβ caused cell damage, while ELVs protected and restored gene expression as in mouse. Our data show OAβ activates senescence as reflected by enhanced expression of p16INK4a, MMP1, p53, p21, p27 and Il-6 and of <span>senescence-associated secretory phenotype</span> (SASP) secretome, followed by RPE and PRC demise and that elovanoids 32 and 34 blunt these events and elicits protection. In addition, ELVs counteracted OAβ-induced expression of genes engaged in AMD, autophagy and extracellular matrix (ECM) remodeling. Overall, our data uncovered that ELVs downplay OAβ-senescence program induction and inflammatory transcriptional events and protect RPE cells and PRC, and therefore have potential as a possible therapeutic avenue for AMD.</span></p>
Additive and mostly adaptive plastic responses of gene expression to multiple stress in Tribolium castaneum
Gene expression is known to be highly responsive to the environment and important for adjustment of metabolism but there is also growing evidence that differences in gene regulation contribute to species divergence and differences among locally adapted populations. However, most studies so far investigated populations when divergence had already occurred. Selection acting on expression levels at the onset of adaptation to an environmental change has not been characterized. Understanding the mechanisms is further complicated by the fact that environmental change is often multivariate, meaning that organisms are exposed to multiple stressors simultaneously with potentially interactive effects. Here we use a novel approach by combining fitness and whole-transcriptome data in a large-scale experiment to investigate responses to drought, heat and their combination in Tribolium castaneum . We found that fitness was reduced by both stressors and their combined effect was almost additive. Expression data showed that stressor responses were acting independently and did not interfere physiologically. Since we measured expression and fitness within the same individuals, we were able to estimate selection on gene expression levels. We found that variation in fitness can be attributed to gene expression variation and that selection pressures were environment dependent and opposite between control and stress conditions. We could further show that plastic responses of expression were largely adaptive, i.e. in the direction that should increase fitness.
Data from: Protein expression parallels thermal tolerance and ecologic changes in the diversification of a diving beetle species complex
Physiological changes associated with evolutionary and ecological processes such as diversification, range expansion or speciation are still incompletely understood, especially for non-model species. Here we study differences in protein expression in response to temperature in a western Mediterranean diving beetle species complex, using two-dimensional differential gel electrophoresis with one Moroccan and one Iberian population each of Agabus ramblae and Agabus brunneus. We identified proteins with significant expression differences after thermal treatments comparing them with a reference EST library generated from one of the species of the complex (A. ramblae). The colonisation during the Middle Pleistocene of the Iberian peninsula by A. ramblae, where maximum temperatures and seasonality are lower than in the ancestral north African range, was associated with changes in the response to 27 °C in proteins related to energy metabolism. The subsequent speciation of A. brunneus from within populations of Iberian A. ramblae was associated with changes in the expression of several stress-related proteins (mostly chaperons) when exposed to 4 °C. These changes are in agreement with the known tolerance to lower temperatures of A. brunneus, which occupies a larger geographical area with a wider range of climatic conditions. In both cases, protein expression changes paralleled the evolution of thermal tolerance and the climatic conditions experienced by the species. However, although the colonisation of the Iberian peninsula did not result in morphological change, the speciation process of A. brunneus within Iberia involved genetic isolation and substantial differences in male genitalia and body size and shape.
Data from: MC1R variants affect the expression of melanocortin and melanogenic genes and the association between melanocortin genes and coloration
The melanocortin-1 receptor (MC1R) gene influences coloration by altering the expression of genes acting downstream in the melanin synthesis. MC1R belongs to the melanocortin system, a genetic network coding for the ligands that regulate MC1R and other melanocortin receptors controlling different physiological and behavioural traits. The impact of MC1R variants on these regulatory melanocortin genes was never considered, even though MC1R mutations could alter the influence of these genes on coloration (e.g. by decreasing MC1R response to melanocortin ligands). Using barn owl growing feathers, we investigated the differences between MC1R genotypes in the (co)expression of six melanocortin and nine melanogenic-related genes and in the association between melanocortin gene expression and phenotype (feather pheomelanin content). Compared to the MC1R rufous allele, responsible for reddish coloration, the white allele was not only associated with an expected lower expression of melanogenic-related genes (TYR, TYRP1, OCA2, SLC45A2, KIT, DCT) but also with a lower MC1R expression and a higher expression of ASIP, the MC1R antagonist. More importantly, the expression of PCSK2, responsible for the maturation of the MC1R agonist, α-melanocyte-stimulating hormone, was positively related to pheomelanin content in MC1R white homozygotes but not in individuals carrying the MC1R rufous allele. These findings indicate that MC1R mutations not only alter the expression of melanogenic-related genes but also the association between coloration and the expression of melanocortin genes upstream of MC1R. This suggests that MC1R mutations can modulate the regulation of coloration by the pleiotropic melanocortin genes, potentially decoupling the often-observed associations between coloration and other phenotypes.
Data from: Social foraging extends associative odor-food memory expression in an automated learning assay for Drosophila melanogaster
<p>Animals socially interact during foraging and share information about the quality and location of food sources. The mechanisms of social information transfer during foraging have been mostly studied at the behavioral level, and its underlying neural mechanisms are largely unknown. Fruit flies have become a model for studying the neural bases of social information transfer, because they provide a large genetic toolbox to monitor and manipulate neuronal activity, and they show a rich repertoire of social behaviors. Fruit flies aggregate, they use social information for choosing a suitable mating partner and oviposition site, and they show better aversive learning when in groups. However, the effects of social interactions on associative odor–food learning have not yet been investigated. Here, we present an automated learning and memory assay for walking flies that allows the study of the effect of group size on social interactions and on the formation and expression of associative odor–food memories. We found that both inter-fly attraction and the duration of odor–food memory expression increase with group size. This study opens up opportunities to investigate how social interactions during foraging are relayed in the neural circuitry of learning and memory expression.</p>
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Allen Brain Atlas
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Annotated Behaviour and Observability Dataset (ABODe)
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