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Evolutionary Applications

Dustin J Marshall, Scott C Burgess, Tim Connallon
Most organisms have complex life cycles, and in marine taxa, larval life-history stages tend to be more sensitive to environmental stress than adult (reproductive) life-history stages. While there are several models of stage-specific adaptation across the life history, the extent to which differential sensitivity to environmental stress (defined here as reductions in absolute fitness across the life history) affects the tempo of adaptive evolution to change remains unclear. We used a heuristic model to explore how commonly observed features associated with marine complex life histories alter a population's capacity to cope with environmental change...
October 2016: Evolutionary Applications
Sinéad Collins
I use an individual-based model to investigate the evolution of cell division rates in asexual populations under chronic environmental enrichment. I show that maintaining increased growth rates over hundreds of generations following environmental improvement can be limited by increases in cellular damage associated with more rapid reproduction. In the absence of further evolution to either increase damage tolerance or decrease the cost of repair or rate of damage, environmental improvement does not reliably lead to long-term increases in reproductive rate in microbes...
October 2016: Evolutionary Applications
Hollie M Putnam, Jennifer M Davidson, Ruth D Gates
As climate change challenges organismal fitness by creating a phenotype-environment mismatch, phenotypic plasticity generated by epigenetic mechanisms (e.g., DNA methylation) can provide a temporal buffer for genetic adaptation. Epigenetic mechanisms may be crucial for sessile benthic marine organisms, such as reef-building corals, where ocean acidification (OA) and warming reflect in strong negative responses. We tested the potential for scleractinian corals to exhibit phenotypic plasticity associated with a change in DNA methylation in response to OA...
October 2016: Evolutionary Applications
Luisa Listmann, Maxime LeRoch, Lothar Schlüter, Mridul K Thomas, Thorsten B H Reusch
Temperature has a profound effect on the species composition and physiology of marine phytoplankton, a polyphyletic group of microbes responsible for half of global primary production. Here, we ask whether and how thermal reaction norms in a key calcifying species, the coccolithophore Emiliania huxleyi, change as a result of 2.5 years of experimental evolution to a temperature ≈2°C below its upper thermal limit. Replicate experimental populations derived from a single genotype isolated from Norwegian coastal waters were grown at two temperatures for 2...
October 2016: Evolutionary Applications
Morgan W Kelly, Melissa B DeBiasse, Vidal A Villela, Hope L Roberts, Colleen F Cecola
Trade-offs may influence both physiological and evolutionary responses to co-occurring stressors, but their effects on both plastic and adaptive responses to climate change are poorly understood. To test for genetic and physiological trade-offs incurred in tolerating multiple stressors, we hybridized two populations of the intertidal copepod Tigriopus californicus that were divergent for both heat and salinity tolerance. Starting in the F2 generation, we selected for increased tolerance of heat, low salinity, and high salinity in replicate lines...
October 2016: Evolutionary Applications
Leela J Chakravarti, Michael D Jarrold, Emma M Gibbin, Felix Christen, Gloria Massamba-N'Siala, Pierre U Blier, Piero Calosi
Human-assisted, trans-generational exposure to ocean warming and acidification has been proposed as a conservation and/or restoration tool to produce resilient offspring. To improve our understanding of the need for and the efficacy of this approach, we characterized life-history and physiological responses in offspring of the marine polychaete Ophryotrocha labronica exposed to predicted ocean warming (OW: + 3°C), ocean acidification (OA: pH -0.5) and their combination (OWA: + 3°C, pH -0.5), following the exposure of their parents to either control conditions (within-generational exposure) or the same conditions (trans-generational exposure)...
October 2016: Evolutionary Applications
Melanie M Lloyd, April D Makukhov, Melissa H Pespeni
Standing genetic variation may allow for rapid evolutionary response to the geologically unprecedented changes in global conditions. However, there is little known about the consequences of such rapid evolutionary change. Here, we measure genetic responses to experimental low and high pCO 2 levels in purple sea urchin larvae, Strongylocentrotus purpuratus. We found greater loss of nucleotide diversity in high pCO 2 levels (18.61%; 900 μatm) compared to low pCO 2 levels (10.12%; 400 μatm). In the wild, this loss could limit the evolutionary capacity of future generations...
October 2016: Evolutionary Applications
Pierre De Wit, Sam Dupont, Peter Thor
Ocean acidification is expected to have dramatic impacts on oceanic ecosystems, yet surprisingly few studies currently examine long-term adaptive and plastic responses of marine invertebrates to pCO 2 stress. Here, we exposed populations of the common copepod Pseudocalanus acuspes to three pCO 2 regimes (400, 900, and 1550 μatm) for two generations, after which we conducted a reciprocal transplant experiment. A de novo transcriptome was assembled, annotated, and gene expression data revealed that genes involved in RNA transcription were strongly down-regulated in populations with long-term exposure to a high pCO 2 environment, even after transplantation back to control levels...
October 2016: Evolutionary Applications
Lisa N S Shama, Felix C Mark, Anneli Strobel, Ana Lokmer, Uwe John, K Mathias Wegner
Transgenerational effects can buffer populations against environmental change, yet little is known about underlying mechanisms, their persistence or the influence of environmental cue timing. We investigated mitochondrial respiratory capacity (MRC) and gene expression of marine sticklebacks that experienced acute or developmental acclimation to simulated ocean warming (21°C) across three generations. Previous work showed that acute acclimation of grandmothers to 21°C led to lower (optimized) offspring MRCs...
October 2016: Evolutionary Applications
Araceli Rodríguez-Romero, Michael D Jarrold, Gloria Massamba-N'Siala, John I Spicer, Piero Calosi
Little is known of the capacity that marine metazoans have to evolve under rapid p CO 2 changes. Consequently, we reared a marine polychaete, Ophryotrocha labronica, previously cultured for approximately 33 generations under a low/variable pH regime, under elevated and low p CO 2 for six generations. The strain used was found to be tolerant to elevated p CO 2 conditions. In generations F1 and F2 females' fecundity was significantly lower in the low p CO 2 treatment. However, from generation F3 onwards there were no differences between p CO 2 treatments, indicating that trans-generational effects enabled the restoration and maintenance of reproductive output...
October 2016: Evolutionary Applications
Jennifer M Donelson, Marian Wong, David J Booth, Philip L Munday
Predicting the impacts of climate change to biological systems requires an understanding of the ability for species to acclimate to the projected environmental change through phenotypic plasticity. Determining the effects of higher temperatures on individual performance is made more complex by the potential for environmental conditions experienced in previous and current generations to independently affect phenotypic responses to high temperatures. We used a model coral reef fish (Acanthochromis polyacanthus) to investigate the influence of thermal conditions experienced by two generations on reproductive output and the quality of offspring produced by adults...
October 2016: Evolutionary Applications
Noelle M Lucey, Chiara Lombardi, Maurizio Florio, Lucia DeMarchi, Matteo Nannini, Simon Rundle, Maria Cristina Gambi, Piero Calosi
Ocean acidification (OA) is likely to exert selective pressure on natural populations. Our ability to predict which marine species will adapt to OA and what underlies this adaptive potential is of high conservation and resource management priority. Using a naturally low-pH vent site in the Mediterranean Sea (Castello Aragonese, Ischia) mirroring projected future OA conditions, we carried out a reciprocal transplant experiment to investigate the relative importance of phenotypic plasticity and local adaptation in two populations of the sessile, calcifying polychaete Simplaria sp...
October 2016: Evolutionary Applications
Jacqueline L Padilla-Gamiño, Juan Diego Gaitán-Espitia, Morgan W Kelly, Gretchen E Hofmann
To project how ocean acidification will impact biological communities in the future, it is critical to understand the potential for local adaptation and the physiological plasticity of marine organisms throughout their entire life cycle, as some stages may be more vulnerable than others. Coralline algae are ecosystem engineers that play significant functional roles in oceans worldwide and are considered vulnerable to ocean acidification. Using different stages of coralline algae, we tested the hypothesis that populations living in environments with higher environmental variability and exposed to higher levels of pCO 2 would be less affected by high pCO 2 than populations from a more stable environment experiencing lower levels of pCO 2...
October 2016: Evolutionary Applications
Piero Calosi, Pierre De Wit, Peter Thor, Sam Dupont
Projections of marine biodiversity and implementation of effective actions for its maintenance in the face of current rapid global environmental change are constrained by our limited understanding of species' adaptive responses, including transgenerational plasticity, epigenetics and natural selection. This special issue presents 13 novel studies, which employ experimental and modelling approaches to (i) investigate plastic and evolutionary responses of marine species to major global change drivers; (ii) ask relevant broad eco-evolutionary questions, implementing multiple species and populations studies; (iii) show the advantages of using advanced experimental designs and tools; (iv) construct novel model organisms for marine evolution; (v) help identifying future challenges for the field; and (vi) highlight the importance of incorporating existing evolutionary theory into management solutions for the marine realm...
October 2016: Evolutionary Applications
Victoria L Pritchard, Jaakko Erkinaro, Matthew P Kent, Eero Niemelä, Panu Orell, Sigbjørn Lien, Craig R Primmer
Many wild Atlantic salmon (Salmo salar) populations are threatened by introgressive hybridization from domesticated fish that have escaped from aquaculture facilities. A detailed understanding of the hybridization dynamics between wild salmon and aquaculture escapees requires discrimination of different hybrid classes; however, markers currently available to discriminate the two types of parental genome have limited power to do this. Using a high-density Atlantic salmon single nucleotide polymorphism (SNP) array, in combination with pooled-sample allelotyping and an Fst outlier approach, we identified 200 SNPs that differentiated an important Atlantic salmon stock from the escapees potentially hybridizing with it...
September 2016: Evolutionary Applications
Cécile Gracianne, Pierre-Loup Jan, Sylvain Fournet, Eric Olivier, Jean-François Arnaud, Catherine Porte, Sylvie Bardou-Valette, Marie-Christine Denis, Eric J Petit
Studying wild pathogen populations in natural ecosystems offers the opportunity to better understand the evolutionary dynamics of biotic diseases in crops and to enhance pest control strategies. We used simulations and genetic markers to investigate the spatial and temporal population genetic structure of wild populations of the beet cyst nematode Heterodera schachtii on a wild host plant species, the sea beet (Beta vulgaris spp. maritima), the wild ancestor of cultivated beets. Our analysis of the variation of eight microsatellite loci across four study sites showed that (i) wild H...
September 2016: Evolutionary Applications
Ricardo S Ramiro, Henrique Costa, Isabel Gordo
Small-colony variants (SCVs) are commonly observed in evolution experiments and clinical isolates, being associated with antibiotic resistance and persistent infections. We recently observed the repeated emergence of Escherichia coli SCVs during adaptation to the interaction with macrophages. To identify the genetic targets underlying the emergence of this clinically relevant morphotype, we performed whole-genome sequencing of independently evolved SCV clones. We uncovered novel mutational targets, not previously associated with SCVs (e...
September 2016: Evolutionary Applications
Annika Perry, Anna V Brown, Stephen Cavers, Joan E Cottrell, Richard A Ennos
Spatial heterogeneity in pathogen pressure leads to genetic variation in, and evolution of, disease-related traits among host populations. In contrast, hosts are expected to be highly susceptible to exotic pathogens as there has been no evolution of defence responses. Host response to pathogens can therefore be an indicator of a novel or endemic pathosystem. Currently, the most significant threat to native British Scots pine (Pinus sylvestris) forests is Dothistroma needle blight (DNB) caused by the foliar pathogen Dothistroma septosporum which is presumed to be exotic...
September 2016: Evolutionary Applications
Lisa M Komoroske, Ken M Jeffries, Richard E Connon, Jason Dexter, Matthias Hasenbein, Christine Verhille, Nann A Fangue
As global change alters multiple environmental conditions, predicting species' responses can be challenging without understanding how each environmental factor influences organismal performance. Approaches quantifying mechanistic relationships can greatly complement correlative field data, strengthening our abilities to forecast global change impacts. Substantial salinity increases are projected in the San Francisco Estuary, California, due to anthropogenic water diversion and climatic changes, where the critically endangered delta smelt (Hypomesus transpacificus) largely occurs in a low-salinity zone (LSZ), despite their ability to tolerate a much broader salinity range...
September 2016: Evolutionary Applications
Stéphane Cornet, Carine Brouat, Christophe Diagne, Nathalie Charbonnel
Immunity is at the core of major theories related to invasion biology. Among them, the evolution of increased competitive ability (EICA) and EICA-refined hypotheses have been used as a reference work. They postulate that the release from pathogens often experienced during invasion should favour a reallocation of resources from (costly) immune defences to beneficial life-history traits associated with invasive potential. We review studies documenting immune changes during animal invasions. We describe the designs and approaches that have been applied and discuss some reasons that prevent drawing generalized conclusions regarding EICA hypotheses...
September 2016: Evolutionary Applications
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