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REV-ERBalpha mediates complement expression and circadian regulation of microglial synaptic phagocytosis
— 2020-12-01 <p>The circadian clock has been shown to regulate various aspects of brain health including microglial and astrocyte activation. Here we report that deletion of the master clock protein BMAL1 induces robust increases in the expression of complement genes such as <i>C3, C4b </i>and <i>C1q</i> in the hippocampus. Loss of downstream REV-ERBa-mediated transcriptional repression led to increases in <i>C4b </i>in neurons and astrocytes as well as C3 protein in microglia and astrocytes. REV-ERBa deletion induced complement <i>C3/C4b </i>gene expression and increased microglial phagocytosis of synapses in the CA3 region of the hippocampus. Finally, we observed diurnal variation in the degree of microglial synaptic phagocytosis in wild type mice which was abrogated by REV-ERBα deletion. This work uncovers the BMAL1-REV-ERBa axis as a regulator of complement expression and synaptic phagocytosis in the brain, thereby illuminating a novel mechanism of synaptic regulation by the circadian clock.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Interspecific and intraspecific comparisons reveal the importance of evolutionary context in sunfish brain form divergence
— 2021-01-21 <p>Habitats can select for specialized phenotypic characteristics in animals. However, the consistency of evolutionary responses to particular environmental conditions remains difficult to predict. One trait of great ecological importance is brain form, which is expected to vary between habitats that differ in their cognitive requirements. Here we compared divergence in brain form and oral jaw size across a common littoral-pelagic ecological axis in two sunfishes at both the intraspecific and interspecific levels. Brain form differed between habitats at every level of comparison, however divergence was inconsistent, despite consistent differences in oral jaw size. Pumpkinseed and bluegill species differed in cerebellum, optic tectum, and olfactory bulb size. These differences are consistent with a historical ecological divergence because they did not manifest between littoral and pelagic ecotypes within either species, suggesting constraints on changes to these regions over short evolutionary time scales. There were also differences in brain form between conspecific ecotypes, but they were inconsistent between species. Littoral pumpkinseed had larger brains than their pelagic counterpart, and littoral bluegill had smaller telencephalons than their pelagic counterpart. Inconsistent brain form divergence between conspecific ecotypes of pumpkinseed and bluegill sharing a common littoral-pelagic habitat axis suggests that contemporary ecological conditions and historic evolutionary context interact to influence evolutionary changes in brain form in fishes.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Population and community-level rarity have opposing effects on pollinator visitation and seed set
— 2020-03-26 <ol> <li>When can small, isolated populations overcome the negative consequences of rarity? Despite considerable effort to understand threats to rare species, few studies consider how community context alters these threats. Plant-pollinator interactions offer the opportunity to test the effect of community context on rare species success, as plant-pollinator dynamics are thought to be influenced by neighboring plants, both through competition for pollinators (reducing success in small populations) and attraction of potential pollinators (increasing success in small populations). Here, we test these predictions by experimentally decoupling community-level rarity (relative abundance) from population-level rarity (population size) in experimental two-species fragments.</li> <li>We created experimental plant communities varying independently in population rarity (population size) and community rarity (relative abundance) of two annual plant species. We isolated plant roots to eliminate resource competition. We then compared the effects of population size vs. relative abundance on pollinator visitation rates and an estimate of seed production.</li> <li>Both species had greatest pollinator visitation in large populations, but the negative effects of population rarity on visitation were partially offset when the neighboring species was more abundant – community rarity offset the impacts of population rarity for the most common group of pollinators, solitary bees. These visitation trends impacted seed production for one species. When at low relative abundance, <i>Polanisia dodecandra</i> had higher seed set, matching increased visitation by solitary bees. <i>Chamaecrista fasciculata </i>showed no change in seed production with population- or community level rarity.</li> <li style="margin-bottom:11px;">Synthesis: Our results suggest that the surrounding community can offset the negative effects of low absolute abundance on fitness when neighboring species are more abundant, and may ultimately maintain diversity even in fragmented ecological communities.</li> </ol> https://creativecommons.org/publicdomain/zero/1.0/
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Toxplasma gondii wild-type vs. ASH4 knockout untargeted metabolomics raw data
— 2021-05-10 <p>The intracellular protozoan parasite <i>Toxoplasma gondii</i> must scavenge cholesterol and other lipids from the host to facilitate intracellular growth and replication. Enzymes responsible for neutral lipid synthesis have been identified but there is no evidence for enzymes that catalyze lipolysis of cholesterol esters and esterified lipids. Here we characterize several <i>T. gondii</i> serine hydrolases with esterase and thioesterase activities that were previously thought to be depalmitoylating enzymes. We find they do not cleave palmitoyl thiol esters but rather hydrolyze short chain lipid esters. Deletion of one of the hydrolases results in alterations in levels of multiple lipids species. We also identify small molecule inhibitors of these hydrolases and show that treatment of parasites results in phenotypic defects reminiscent of parasites exposed to excess cholesterol or oleic acid. Together, these data characterize enzymes necessary for processing lipids critical for infection and highlight the potential for targeting parasite hydrolases for therapeutic applications.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Oncorhynchus kisutch genetic stock ID SNP baseline
— 2022-01-25 <p>Genetic stock identification (GSI) <span style="background:white;">using genotypes produced from genotyping-by-sequencing of SNP loci</span> has become the gold standard for stock identification in Pacific salmon, which are found in mixed stocks in the ocean. Sequencing platforms currently applied require large batch sizes and multi-day processing in specialized facilities to perform genotyping by the thousands. However, recent advances in third-generation single-molecule sequencing platforms, like the Oxford Nanopore minION, provide base calling on portable, pocket-sized sequencers and promise real-time, in-field stock identification on variable batch sizes. Here we evaluate utility and comparability to established GSI platforms of at-sea stock identification of coho salmon <i>Oncorhynchus kisutch</i> based on targeted SNP amplicon sequencing on the minION platform during a high-sea winter expedition to the Gulf of Alaska. As long read sequencers are not optimized for short amplicons, we concatenate amplicons to increase coverage and throughput. Nanopore sequencing at-sea yielded stock assignment for 50 of the 80 assessed individuals. Nanopore-based SNP calls agreed with Ion Torrent based genotypes in 83.25%, but assignment of individuals to stock of origin only agreed in 61.5% of individuals highlighting inherent challenges of Nanopore sequencing, such as resolution of homopolymer tracts and indels. However, poor representation of assayed coho salmon in the queried baseline dataset contributed to poor assignment confidence on both platforms. Future improvements will focus on lowering turnaround time, accuracy, throughput, and cost, as well as augmentation of the existing baselines. If successfully implemented, Nanopore sequencing will provide an alternative method to the large-scale laboratory approach by providing mobile small batch genotyping to diverse stakeholders.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Plastic changes in the brain after human hand allotransplantation
— 2020-08-19 <p style="text-align:start;text-indent:0px;"><span><span style="font-style:normal;"><span><span style="font-weight:normal;"><span style="letter-spacing:normal;"><span><span><span style="white-space:normal;"><span><span><span>The physiological mechanism after hand transplant was investigated using magnetic resonance imaging and transcranial magnetic stimulation. Somatosensory and motor representations of the upper arm proximal to amputation occupied the hand area before surgery and moved back toward normal position after the surgery. The absent cortical inhibition with amputation increased gradually after surgery. The cortical plastic changes preceded functional recovery and can be used to monitor functional restoration after hand transplant.</span></span></span></span></span></span></span></span></span></span></span></p> https://creativecommons.org/publicdomain/zero/1.0/
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Graminoids vary in functional traits, carbon dioxide and methane fluxes in a restored peatland: implications for modeling carbon storage
— 2022-05-24 <p>1. One metric of peatland restoration success is the re-establishment of a carbon sink, yet considerable uncertainty remains around the timescale of carbon sink trajectories. Conditions post-restoration may promote the establishment of vascular plants such as graminoids, often at greater density than would be found in undisturbed peatlands, with consequences for carbon storage. Although graminoid species are often considered as a single plant functional type (PFT) in land-atmosphere models, our understanding of functional variation among graminoid species is limited, particularly in a restoration context.</p> <p>2. We used a traits-based approach to evaluate graminoid functional variation and to assess whether different graminoid species should be considered a single PFT or multiple types. We tested hypotheses that greenhouse gas fluxes (CO<sub>2</sub>, CH<sub>4</sub>) would vary due to differences in plant traits among five graminoid species in a restored peatland in central Alberta, Canada. We further hypothesized that species would form two functionally distinct groupings based on taxonomy (grass, sedge).</p> <p>3. Differences in gas fluxes among species were primarily driven by variation in leaf physiology related to photosynthetic efficiency and resource-use, and secondarily by plant size. Multivariate analyses did not reveal distinct functional groupings based on taxonomy or environmental preferences. Rather, we identified functional groups defined by plant traits and carbon fluxes that are consistent with ecological strategies related to differences in growth rate, resource-acquisition, and leaf economics, representing plants with either a strategy to grow quickly and invest in resource capture or to prioritize structural investment and resource conservation. These functional groups displayed larger average carbon fluxes compared to graminoid PFTs currently used in modeling.</p> <p>4. Existing PFT designations in peatland models may be more appropriate for pristine or high-latitude systems than those under restoration. Although replacing PFTs with plant traits remains a challenge in peatlands, traits related to leaf physiology and growth rate strategies offer a promising avenue for future applications.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Spontaneous mimicry of live facial expressions: A biological mechanism for emotional contagion
— 2022-11-08 <p>Observation of live facial expressions typically elicits similar expressions (facial mimicry) accompanied by shared emotional experiences (emotional contagion). The model of embodied emotion proposes that emotional contagion and facial mimicry are functionally linked although the neural underpinnings are unknown. To address this knowledge gap we employed two-person (n = 20 dyads) functional near-infrared spectroscopy during live emotive face-processing while also measuring eye-tracking, facial classifications, and ratings of emotion. One partner, “Movie Watcher”, was instructed to emote natural facial expressions while viewing evocative short movie clips. The other partner, “Face Watcher”, viewed the Movie Watcher’s face. Dyadic roles were alternated between partners. Task and rest blocks were implemented by timed epochs of clear and opaque glass that separated partners. Correlations of dyadic facial expressions (r = 0.41) and dyadic affect ratings (r = 0.66) were consistent with findings of both emotional contagion and facial mimicry. Neural correlates of emotional contagion based on covariates of partner ratings included right angular and supramarginal gyri. Neural correlates of mimicry associated with partner facial action units include core face recognition system. Thus, the proposed linkages between facial mimicry and emotional contagion represent separate components of face processing.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data for: Predation risk increases with the domain of danger in conspicuous but not cryptic artificial prey
— 2022-05-25 <p>Determining why some animals form groups while others remain solitary is a longstanding goal in behavioural ecology. Group formation can help mitigate predation risk through a variety of mechanisms, including risk dilution and group vigilance. The ‘selfish herd hypotheses’ proposes that prey can reduce their risk by minimizing the area around which all points in that area are closer to them than to another conspecific (i.e., by minimising their ‘domain of danger’). This hypothesis assumes that an individual’s predation risk is proportional to the size of their domain of danger, however the relationship between risk and proximity to conspecifics may depend on additional factors. Specifically, approaching conspecifics may be costly for prey that rely on crypsis because group formation increases detectability. Using model prey, we experimentally manipulated prey colouration as well as the domain of danger, then tracked their ‘survival’ under natural field conditions. We found that an individual’s predation risk increased with their domain of danger for conspicuous (red) prey, but decreased with the domain of danger in cryptic (green) prey. Our results are consistent with patterns in natural systems and indicate that the relationship between predation risk and domain of danger depends on additional factors like prey colouration.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Foraging on anthropogenic food predicts problem-solving skills in a seabird
— 2022-08-08 <p>Species and populations with greater cognitive performance are more successful at adapting to changing habitats. Accordingly, urban species and populations often outperform their rural counterparts on problem-solving tests. Paradoxically, urban foraging also might be detrimental to the development and integrity of animals’ brains because anthropogenic foods often lack essential nutrients such as the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are important for cognitive performance in mammals and possibly birds. We tested whether urbanization or consumption of EPA and DHA are associated with problem-solving abilities in ring-billed gulls, a seabird that historically exploited marine environments rich in omega-3 fatty acids but now also thrives in urban centres. Using incubating adults nesting across a range of rural to urban colonies with equal access to the ocean, we tested whether urban gulls preferentially consumed anthropogenic food while rural nesters relied on marine organisms. As we expected individual variation in foraging habits within nesting location, we characterized each captured gulls’ diet using stable isotope and fatty acid analyses of their red blood cells. To test their problem-solving abilities, we presented the sampled birds with a horizontal rendition of the string-pull test, a foraging puzzle often used in animal cognitive studies. The isotopic and fatty acid profiles of urban nesters indicated a diet comprising primarily anthropogenic food, whereas the profiles of rural nesters indicated a high reliance on marine organisms. Despite the gulls’ degree of access to urban foraging habitat not predicting solving success, birds with biochemical profiles reflecting anthropogenic food (less DHA and a higher carbon-13 ratio in their red blood cells) had a greater probability of solving the string-pull test. These results suggest that experience foraging on anthropogenic food is the main explanatory factor leading to successful problem-solving, while regular consumption of omega-3s during incubation appears inconsequential.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Latent Transforming Growth Factor β Binding Protein 3 Controls Adipogenesis
— 2022-08-15 <p>Transforming growth factor-beta (TGFβ) is released from cells as part of a trimeric latent complex consisting of TGFβ, the TGFβ propeptides, and either a latent TGFβ binding protein (LTBP) or glycoprotein-A repetitions predominant (GARP) protein. LTBP1 and 3 modulate latent TGFβ function with respect to secretion, matrix localization, and activation and, therefore, are vital for the proper function of the cytokine in a number of tissues. TGFβ modulates stem cell differentiation into adipocytes (adipogenesis), but the potential role of LTBPs in this process has not been studied. We observed that 72 h post adipogenesis initiation <em>Ltbp1</em>, <em>2</em>, and <em>4 </em>expression levels decrease by 74-84%, whereas <em>Ltbp3 </em>expression levels remain constant during adipogenesis. We found that LTBP3 silencing in C3H/10T1/2 cells reduced adipogenesis, as measured by the percentage of cells with lipid vesicles and the expression of the transcription factor peroxisome proliferator-activated receptor gamma (PPARγ). Lentiviral mediated expression of an <em>Ltbp3 </em>mRNA resistant to siRNA targeting rescued the phenotype, validating siRNA specificity. Knockdown (KD) of Ltbp3 expression in 3T3-L1, M2, and primary bone marrow stromal cells (BMSC) indicated a similar requirement for <em>Ltbp3</em>. Epididymal and inguinal white adipose tissue fat pad weights of <em>Ltbp3</em><sup>-/-</sup> mice were reduced by 62% and 57%, respectively, compared to wild-type mice. Inhibition of adipogenic differentiation upon LTBP3 loss is mediated by TGFβ, as TGFβ neutralizing antibody and TGFβ receptor I kinase blockade rescue the LTBP3 KD phenotype. These results indicate that LTBP3 has a TGFβ-dependent function in adipogenesis both in vitro and possibly in vivo. </p> https://creativecommons.org/publicdomain/zero/1.0/
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The cell adhesion molecule Sdk1 shapes assembly of a retinal circuit that detects localized edges
— 2021-09-21 <p>Nearly 50 different mouse retinal ganglion cell (RGC) types sample the visual scene for distinct features. RGC feature selectivity arises from its synapses with a specific subset of amacrine (AC) and bipolar cell (BC) types, but how RGC dendrites arborize and collect input from these specific subsets remains poorly understood. Here we examine the hypothesis that RGCs employ molecular recognition systems to meet this challenge. By combining calcium imaging and type-specific histological stains we define a family of circuits that express the recognition molecule Sidekick 1 (Sdk1) which include a novel RGC type (S1-RGC) that responds to local edges. Genetic and physiological studies revealed that Sdk1 loss selectively disrupts S1-RGC visual responses which result from a loss of excitatory and inhibitory inputs and selective dendritic deficits on this neuron. We conclude that Sdk1 shapes dendrite growth and wiring to help S1-RGCs become feature selective.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Origin of land plants revisited in the light of sequence contamination and missing data
— 2012-08-22 Knowing the closest relatives of land plants is key to understanding the complex adaptations to terrestrial life. Unfortunately, multi-gene analyses yield highly incongruent results, suggesting for instance Charales, Zygnematales, or Coleochaete as the sister-group of land plants. Such controversy may result from the real history of life, in particular closely spaced speciation events, incomplete lineage sorting, gene duplication or horizontal gene transfer. In such cases, the solution resides in improved taxon sampling and sophisticated models of evolution. However, we will show that the quality of data used to infer the phylogeny may also play a major role, creating unnecessary controversy. In particular, the inclusion of contaminant sequences from other species, and of genes with incomplete taxon sampling explains a large part of the discrepancies observed between various studies. The use of a carefully checked and almost complete dataset suggests that land plants are closely related to a group composed of Zygnematales and Coleochaetales. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Multiple origins of sex chromosome fusions correlated with chiasma localization in Habronattus jumping spiders (Araneae: Salticidae)
— 2013-02-28 Entelegyne spiders rarely show fusions yielding neo-Y chromosomes, which M. J. D. White attributed to a constraint in spiders, namely their proximal chiasma localization acting to upset meiotic segregation in males with fusions. Of the 75 taxa of Habronattus and outgroups studied, 47 have X1X20 sex chromosomes in males, 10 have X1X2Y, 15 have X1X2X3Y, 2 have X0, and one has both X1X20 and X1X2X3Y. Chromosome numbers and behavior suggest neo-Ys formed by an autosome-X fusion to make X1X2Y, with a second fusion to an autosome to make X1X2X3Y. Phylogeny shows at least 8-15 gains (or possibly some losses) of neo-Y (i.e. X-autosome fusions), a remarkable number for such a small clade. In contrast to the many X-autosome fusions, at most one autosome-autosome fusion is indicated. Origins of neo-Y are correlated significantly with distal localization of chiasmata, supporting White’s hypothesis that evolution of neo-Y systems is facilitated by looser pairing (distal chiasmata) at meiosis. However, an alternative (or contributing) explanation for the correlation is that X-autosome fusions were selected to permit isolation of male-favored alleles to the neo-Y chromosome, aided by distal chiasmata limiting recombination. This intralocus sexual conflict hypothesis could explain both the many X-autosome fusions, and the stunning complexity of male Habronattus courtship displays. https://creativecommons.org/publicdomain/zero/1.0/
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Data from: New material and systematic re-evaluation of Medusaceratops lokii (Dinosauria: Ceratopsidae) from the Judith River Formation (Campanian, Montana)
— 2017-05-17 Medusaceratops lokii is an enigmatic taxon of ceratopsid represented by partial parietals from the Mansfield bonebed in the Campanian Judith River Formation, Montana. Originally, all ceratopsid material collected from this bonebed was referred to the centrosaurine ceratopsid Albertaceratops, but subsequently two parietals were designated the types of the chasmosaurine, M. lokii, in part, because they were interpreted to have three epiparietals bilaterally. Here we describe new material from the bonebed that allows a systematic revision of the taxon. A revised reconstruction of the frill, informed by newly discovered parietals, reveals that M. lokii had a broad midline ramus and at least five epiparietals (ep) around the margin of the frill, both traits that are characteristic of Centrosaurinae. From medial to lateral, the epiparietal ornamentation consists of a small, variably procurving epiparietal (ep 1), an anterolaterally curving pachyostotic hook (ep 2), a smaller pachyostoic process (ep 3), and two small triangular epiparietals (ep 4 and 5). A phylogenetic analysis of ceratopsids, which is the first to include Medusaceratops, indicates that that M. lokii is a unique, early centrosaurine ceratopsid taxon that is more closely related to Centrosaurini and Pachyrhinosaurini than Nasutoceratopsini. No unequivocal chasmosaurine bones or diagnostic material from any other ceratopsid could be identified from the Mansfield bonebed, suggesting that it represents one of the oldest occurrences of a monodominant accumulation of a centrosaurine ceratopsid on record. https://creativecommons.org/publicdomain/zero/1.0/
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Landscape scale lake surveys of Algonquin Provincial Park
— 2022-11-18 <p>To better understand the status of Lake Trout and Brook Trout populations across the Algonquin Provincial Park landscape 192 index netting surveys were conducted on 161 lakes utilizing standardized multimesh benthic gillnets between the years 2009 and 2022.</p> <p>Index netting was conducted using a depth-stratified randomized site survey design and employed multi-pass sampling on a majority of the lakes to provide the opportunity for occupancy analysis. Two primary netting methods were employed; <a href="https://www.ontario.ca/page/summer-profundal-index-netting-manual" target="_blank" rel="noopener">Summer Profundal Index Netting (SPIN)</a> for Lake Trout populations sampled between 2009-2012; and a modified <a href="https://www.ontario.ca/page/broad-scale-fish-community-monitoring" target="_blank" rel="noopener">Ontario Broadscale Monitoring</a> (BsM) method we refer to as Short Duration Point Sampling (SDPS). The SDPS method uses the large mesh BsM nets (NA1) deployed for a one-hour duration within the same depth strata used in the BsM program with a sampling intensity in each stratum proportional to the surface area. The overall sampling intensity (nets/lake) is greater than that employed in the BsM program as we are interested in lake-specific analyses. </p> <p>This data dryad provides general information on each lake sampled including lake characteristics, lake volumes, netting site locations, and spring water chemistry.  </p> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Your infections are what you eat: how host ecology shapes the helminth parasite communities of lizards
— 2018-12-04 1. Understanding how parasite communities are assembled, and the factors that influence their richness, can improve our knowledge of parasite-host interactions and help to predict the spread of infectious diseases. Previous comparative analyses have found significant influences of host ecology and life history, but focused on a few select host taxa. 2. Host diet and habitat use play key roles in the acquisition of parasitic helminths as many are trophically-transmitted, making these attributes potentially key indicators of infection risk. Given the paucity of comparative studies with non-piscine, non-avian or non-mammalian hosts, it is critical to examine the degree to which host ecology influences parasite communities in other host taxa in order to identify common drivers. 3. We examined helminth diversity in over 350 species of lizards in relation to their body mass, ecology (diet and habitat use), and life history (clutch size, and ovo- or viviparity) using previously published data. 4. Overall, lizard species with herbivorous diets harboured fewer types of helminths (especially larval stages), with similar results for traits that were ultimately strongly associated with diet (host mass and habitat use). Large hosts tended to be herbivores with few helminth types whereas species utilizing arboreal habitats typically consumed some animal matter and hosted more helminths. 5. Understanding how host ecology and life history are related to their parasite assemblages has significant implications for the risk of acquiring novel parasites. Our results indicate an overwhelming influence of host diet such that many helminths may be relatively easily acquired by hosts in new ranges, or through dietary shifts. https://creativecommons.org/publicdomain/zero/1.0/
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Disconnects between ecological theory and data in phenological mismatch research
— 2020-05-20 <p>Climate change may lead to phenological mismatches, where the timing of critical events between interacting species becomes de-synchronized, with potential negative consequences. Evidence documenting negative impacts on fitness is mixed. The Cushing match-mismatch hypothesis, the most common hypothesis underlying these studies, offers testable assumptions and predictions to determine consequences of phenological mismatch when combined with a pre-climate change baseline. Here, we highlight how improved approaches could rapidly advance mechanistic understanding. We find that currently no study has collected the data required to test this hypothesis well, and 71% of studies fail to define a baseline. Experiments that clearly link timing to fitness and test extremes, integration across approaches, and null models would aid robust predictions of shifts with climate change.</p> https://creativecommons.org/publicdomain/zero/1.0/
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Breaking ecological barriers: anthropogenic disturbance leads to habitat transitions, hybridization, and high genetic diversity
— 2020-08-25 <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> https://creativecommons.org/publicdomain/zero/1.0/
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Data from: Genetic architecture of survival and fitness-related traits in two populations of Atlantic salmon
— 2013-06-28 The additive genetic effects of traits can be used to predict evolutionary trajectories, such as responses to selection. Non-additive genetic and maternal environmental effects can also change evolutionary trajectories and influence phenotypes, but these later effects have received less attention by researchers. We partitioned the phenotypic variance of survival and fitness-related traits into additive genetic, non- additive genetic, and maternal environmental effects using a full-factorial breeding design within two allopatric populations of Atlantic salmon (Salmo salar). Maternal environmental effects were large at early life stages, but decreased during development, with non-additive genetic effects being most significant at later juvenile stages (alevin and fry). Non- additive genetic effects were also, on average, larger than additive genetic effects. The populations, generally, did not differ in the trait values or inferred genetic architecture of the traits. Any differences between the populations for trait values could be explained by maternal environmental effects. We discuss if the similarities in architectures of these populations is the result of natural selection across a common juvenile environment. https://creativecommons.org/publicdomain/zero/1.0/

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