bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of phenotypic plasticity in extreme environments
Authors: Chevin Luis-Miguel , Hoffmann Ary A. 
Published: May 2017

Phenotypic plasticity, if adaptive, may allow species to counter the detrimental effects of extreme conditions, but the infrequent occurrence of extreme environments and/or their restriction to low-quality habitats within a species range means that they exert little direct selection on reaction norms. Plasticity could, therefore, be maladaptive under extreme environments, unless genetic correlations are strong between extreme and non-extreme environmental states, and the optimum phenotype changes smoothly with the environment. Empirical evidence suggests that populations and species from more variable environments show higher levels of plasticity that might preadapt them to extremes, but genetic variance for plastic responses can also be low, and genetic variation may not be expressed for some classes of traits under extreme conditions. Much of the empirical literature on plastic responses to extremes has not yet been linked to ecologically relevant conditions, such as asymmetrical fluctuations in the case of temperature extremes. Nevertheless, evolved plastic responses are likely to be important for natural and agricultural species increasingly exposed to climate extremes, and there is an urgent need to collect empirical information and link this to model predictions.This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events'.
Learning from single extreme events
Authors: Altwegg Res , Visser Vernon , Bailey Liam D. , Erni Birgit 
Published: May 2017

Extreme climatic events (ECEs) have a disproportionate effect on ecosystems. Yet much of what we know about the ecological impact of ECEs is based on observing the effects of single extreme events. We examined what characteristics affect the strength of inference that can be drawn from single-event studies, which broadly fell into three categories: opportunistic observational studies initiated after an ECE, long-term observational studies with data before and after an ECE and experiments. Because extreme events occur rarely, inference from such single-event studies cannot easily be made under the usual statistical paradigm that relies on replication and control. However, single-event studies can yield important information for theory development and can contribute to meta-analyses. Adaptive management approaches can be used to learn from single, or a few, extreme events. We identify a number of factors that can make observations of single events more informative. These include providing robust estimates of the magnitude of ecological responses and some measure of climatic extremeness, collecting ancillary data that can inform on mechanisms, continuing to observe the biological system after the ECE and combining observational data with experiments and models. Well-designed single-event studies are an important contribution to our understanding of biological effects of ECEs.
This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events’.
Integrating plant ecological responses to climate extremes from individual to ecosystem levels
Authors: Felton Andrew J. , Smith Melinda D. 
Published: May 2017

Climate extremes will elicit responses from the individual to the ecosystem level. However, only recently have ecologists begun to synthetically assess responses to climate extremes across multiple levels of ecological organization. We review the literature to examine how plant responses vary and interact across levels of organization, focusing on how individual, population and community responses may inform ecosystem-level responses in herbaceous and forest plant communities. We report a high degree of variability at the individual level, and a consequential inconsistency in the translation of individual or population responses to directional changes in community- or ecosystem-level processes. The scaling of individual or population responses to community or ecosystem responses is often predicated upon the functional identity of the species in the community, in particular, the dominant species. Furthermore, the reported stability in plant community composition and functioning with respect to extremes is often driven by processes that operate at the community level, such as species niche partitioning and compensatory responses during or after the event. Future research efforts would benefit from assessing ecological responses across multiple levels of organization, as this will provide both a holistic and mechanistic understanding of ecosystem responses to increasing climatic variability.
This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events’.
Climate change, climatic variation and extreme biological responses
Authors: Palmer Georgina , Platts Philip J. , Brereton Tom , Chapman Jason W. , Dytham Calvin , Fox Richard , Pearce-Higgins James W. , Roy David B. , Hill Jane K. , Thomas Chris D. 
Published: May 2017

Extreme climatic events could be major drivers of biodiversity change, but it is unclear whether extreme biological changes are (i) individualistic (species- or group-specific), (ii) commonly associated with unusual climatic events and/or (iii) important determinants of long-term population trends. Using population time series for 238 widespread species (207 Lepidoptera and 31 birds) in England since 1968, we found that population ‘crashes’ (outliers in terms of species' year-to-year population changes) were 46% more frequent than population ‘explosions’. (i) Every year, at least three species experienced extreme changes in population size, and in 41 of the 44 years considered, some species experienced population crashes while others simultaneously experienced population explosions. This suggests that, even within the same broad taxonomic groups, species are exhibiting individualistic dynamics, most probably driven by their responses to different, short-term events associated with climatic variability. (ii) Six out of 44 years showed a significant excess of species experiencing extreme population changes (5 years for Lepidoptera, 1 for birds). These ‘consensus years’ were associated with climatically extreme years, consistent with a link between extreme population responses and climatic variability, although not all climatically extreme years generated excess numbers of extreme population responses. (iii) Links between extreme population changes and long-term population trends were absent in Lepidoptera and modest (but significant) in birds. We conclude that extreme biological responses are individualistic, in the sense that the extreme population changes of most species are taking place in different years, and that long-term trends of widespread species have not, to date, been dominated by these extreme changes.
This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events’.
Evolution caused by extreme events
Authors: Grant Peter R. , Grant B. Rosemary , Huey Raymond B. , Johnson Marc T. J. , Knoll Andrew H. , Schmitt Johanna 
Published: May 2017

Extreme events can be a major driver of evolutionary change over geological and contemporary timescales. Outstanding examples are evolutionary diversification following mass extinctions caused by extreme volcanism or asteroid impact. The evolution of organisms in contemporary time is typically viewed as a gradual and incremental process that results from genetic change, environmental perturbation or both. However, contemporary environments occasionally experience strong perturbations such as heat waves, floods, hurricanes, droughts and pest outbreaks. These extreme events set up strong selection pressures on organisms, and are small-scale analogues of the dramatic changes documented in the fossil record. Because extreme events are rare, almost by definition, they are difficult to study. So far most attention has been given to their ecological rather than to their evolutionary consequences. We review several case studies of contemporary evolution in response to two types of extreme environmental perturbations, episodic (pulse) or prolonged (press). Evolution is most likely to occur when extreme events alter community composition. We encourage investigators to be prepared for evolutionary change in response to rare events during long-term field studies.This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events’.
Quantifying thermal extremes and biological variation to predict evolutionary responses to changing climate
Authors: Kingsolver Joel G. , Buckley Lauren B. 
Published: May 2017

Central ideas from thermal biology, including thermal performance curves and tolerances, have been widely used to evaluate how changes in environmental means and variances generate changes in fitness, selection and microevolution in response to climate change. We summarize the opportunities and challenges for extending this approach to understanding the consequences of extreme climatic events. Using statistical tools from extreme value theory, we show how distributions of thermal extremes vary with latitude, time scale and climate change. Second, we review how performance curves and tolerances have been used to predict the fitness and evolutionary responses to climate change and climate gradients. Performance curves and tolerances change with prior thermal history and with time scale, complicating their use for predicting responses to thermal extremes. Third, we describe several recent case studies showing how infrequent extreme events can have outsized effects on the evolution of performance curves and heat tolerance. A key issue is whether thermal extremes affect reproduction or survival, and how these combine to determine overall fitness. We argue that a greater focus on tails—in the distribution of environmental extremes, and in the upper ends of performance curves—is needed to understand the consequences of extreme events.
This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events’.
Effects of extreme weather on two sympatric Australian passerine bird species
Authors: Gardner Janet L. , Rowley Eleanor , de Rebeira Perry , de Rebeira Alma , Brouwer Lyanne 
Published: May 2017

Despite abundant evidence that natural populations are responding to climate change, there are few demonstrations of how extreme climatic events (ECEs) affect fitness. Climate warming increases adverse effects of exposure to high temperatures, but alsoreducesexposure to cold ECEs. Here, we investigate variation in survival associated with severity of summer and winter conditions, and whether survival is better predicted by ECEs than mean temperatures using data from two coexisting bird species monitored over 37 years in southwestern Australia, red-winged fairy-wrens,Malurus elegansand white-browed scrubwrens,Sericornis frontalis. Changes in survival were associated with temperature extremes more strongly than average temperatures. In scrubwrens, winter ECEs were associated with survival within the same season. In both species, survival was associated with body size, and there was evidence that size-dependent mortality was mediated by carry-over effects of climate in the previous season. For fairy-wrens, mean body size declined over time but this could not be explained by size-dependent mortality as the effects of body size on survival were consistently positive. Our study demonstrates how ECEs can have individual-level effects on survival that are not reflected in long-term morphological change, and the same climatic conditions can affect similar-sized, coexisting species in different ways.This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events’.
The Human Cell Atlas
Authors: Regev Aviv , Teichmann Sarah A. , Lander Eric S. , Amit Ido , Benoist Christophe , Birney Ewan , Bodenmiller Bernd , Campbell Peter , Carninci Piero , Clatworthy Menna , Clevers Hans , Deplancke Bart , Dunham Ian , Eberwine James , Eils Roland , Enard Wolfgang , Farmer Andrew , Fugger Lars , Göttgens Berthold , Hacohen Nir , Haniffa Muzlifah , Hemberg Martin , Kim Seung , Klenerman Paul , Kriegstein Arnold , Lein Ed , Linnarsson Sten , Lundeberg Joakim , Majumder Partha , Marioni John C. , Merad Miriam , Mhlanga Musa , Nawijn Martijn , Netea Mihai , Nolan Garry , Pe’er Dana , Phillipakis Anthony , Ponting Chris P. , Quake Steve , Reik Wolf , Rozenblatt-Rosen Orit , Sanes Joshua , Satija Rahul , Schumacher Ton N. , Shalek Alex , Shapiro Ehud , Sharma Padmanee , Shin Jay W. , Stegle Oliver , Stratton Michael , Stubbington Michael J. T. , van Oudenaarden Alexander , Wagner Allon , Watt Fiona , Weissman Jonathan , Wold Barbara , Xavier Ramnik , Yosef Nir ,   the Human Cell Atlas Meeting Participants
Published: May 2017

AbstractThe recent advent of methods for high-throughput single-cell molecular profiling has catalyzed a growing sense in the scientific community that the time is ripe to complete the 150-year-old effort to identify all cell types in the human body, by undertaking a Human Cell Atlas Project as an international collaborative effort. The aim would be to define all human cell types in terms of distinctive molecular profiles (e.g., gene expression) and connect this information with classical cellular descriptions (e.g., location and morphology). A comprehensive reference map of the molecular state of cells in healthy human tissues would propel the systematic study of physiological states, developmental trajectories, regulatory circuitry and interactions of cells, as well as provide a framework for understanding cellular dysregulation in human disease. Here we describe the idea, its potential utility, early proofs-of-concept, and some design considerations for the Human Cell Atlas.
Low-cost HPV testing and the prevalence of cervical infection in asymptomatic populations in Guatemala
Authors: Lou Hong , Gharzouzi Eduardo , Guerra Sarita Polo , Domgue Joël Fokom , Torres-Gonzalez Edmundo , Sawitzke Julie , Villagran Guillermo , Garland Lisa , Boland Joseph , Wagner Sarah , Martinez Joanna , Rosas Héctor , Troxler Jami , McMillen Heidi , Kessing Bailey , Alvirez Enrique , Castillo Miriam , Morales Hesler , Argueta Victor , Rosingh Andert , van Aerde-van Nunen Femke J.H.B. , Pinedo Herbert M. , Lopez Griselda , Schiffman Mark , Dean Michael , Orozco Roberto 
Published: May 2017

ABSTRACTBackgroundA low cost and accurate method for detecting high-risk (HR) HPV is important to permit HPV testing for cervical cancer prevention. We validated a low-cost commercially available HPV method (H13, Hybribio, Hong Kong) and determined the distribution of HPV infections in over 1717 cancer-free women in Guatemala.MethodsH13 results were compared with two more established HPV tests: (Xpert™ (Cepheid) and SPF10-LIPA25™ (DDL)) in 40 mainly known positive specimens. HR-HPV was detected in cervical samples from 1717 cancer-free women receiving Pap smears using the Hybribio™ realtime PCR assay of 13 HR types. Selected HPV positive samples were sequenced to determine viral type.ResultsThe Hybribio H13 Assay showed 93% identical results with Xpert, and 89% with SPF10-LIPA25. A total of 13% (226/1717) of women tested HPV+. The highest prevalence was found in younger women (<30 years, 22 %) and older ones (≥60 years, 15%). The six most common HR-HPV types among the 148 HPV+ typed were HPV16 (22%), HPV18 (11%), HPV39 (11%), HPV58 (10%), HPV52 (8%), and HPV45 (8%).ConclusionsThe Hybribio Assay was low cost, and accurate in testing for HR-HPV infection. As in most places, HPV16 was the most prevalent HR type in Guatemala and the age-specific prevalence curve peaked in younger ages.HighlightsA low cost and accurate method, Hybribio Assay, could be used for CC testing in low income regions.A total of 13% of cancer-free women were HPV+ and positivity was associated with younger age (<30 years old) in Guatemala.HPV16 was the major prevalent type.
Attention is required for knowledge-based sequential grouping of syllables into words
Authors: Ding Nai , Pan Xunyi , Luo Cheng , Su Naifei , Zhang Wen , Zhang Jianfeng 
Published: May 2017

AbstractHow the brain sequentially groups sensory events into temporal chunks and how this process is modulated by attention are fundamental questions in cognitive neuroscience. Sequential grouping includes bottom-up primitive grouping and top-down knowledge-based grouping. In speech perception, grouping acoustic features into syllables can rely on bottom-up acoustic continuity cues but grouping syllables into words critically relies on the listener’s lexical knowledge. This study investigates whether top-down attention is required to apply lexical knowledge to group syllables into words, by concurrently monitoring neural entrainment to syllables and words using electroencephalography (EEG). When attention is directed to a competing speech stream or cross-modally to a silent movie, neural entrainment to syllables is weakened but neural entrainment to words largely diminishes. These results strongly suggest that knowledge-based grouping of syllables into words requires top-down attention and is a bottleneck for the neural processing of unattended speech.
Neuronal inhibition of the autophagy nucleation complex extends lifespan in post-reproductiveC. elegans
Authors: Wilhelm Thomas , Byrne Jonathan , Medina Rebeca , Kolundzic Ena , Geisinger Johannes , Hajduskova Martina , Tursun Baris , Richly Holger 
Published: May 2017

AbstractAutophagy is a ubiquitous catabolic process, which causes cellular bulk degradation of cytoplasmic components and thereby regulates cellular homeostasis. Inactivation of autophagy has been linked with detrimental effects to cells and organisms. The antagonistic pleiotropy theory postulates that fitness promoting genes during youth are harmful during aging (Williams 1957). On this basis we examined genes mediating post-reproductive longevity using an RNA interference screen. From this screen we identified 30 novel regulators of post-reproductive longevity includingpha-4. Through downstream analysis ofpha-4we identify that genes governing the early stages of autophagy up until the stage of vesicle nucleation, such asbec-1, strongly extend both lifespan and healthspan. Further, our data demonstrates that the improvements in health and longevity are mediated through the neurons - resulting in reduced neurodegeneration and sarcopenia. We propose that autophagy switches from advantageous to harmful in the context of an age-associated dysfunction.
Sex differentiation in grayling (Salmonidae) goes through an all-male stage and is delayed in genetic males who instead grow faster
Authors: Maitre Diane , Selmoni Oliver M. , Uppal Anshu , da Cunha Lucas Marques , Wilkins Laetitia G. E. , Roux Julien , Mobley Kenyon B. , Knörr Susanne , Robinson-Rechavi Marc , Wedekind Claus 
Published: May 2017

AbstractFish can be threatened by distorted sex ratios that arise during sex differentiation. It is therefore important to understand sex determination and differentiation, especially in river-dwelling fish that are often exposed to environmental factors that may interfere with sex differentiation. However, sex differentiation is not sufficiently understood in keystone taxa such as the Thymallinae, one of the three salmonid subfamilies. Here we study a wild grayling (Thymallus thymallus) population that suffers from distorted sex ratios. We found sex determination in the wild and in captivity to be genetic and linked to the sdY locus. We therefore studied sex-specific gene expression in embryos and early larvae that were bred and raised under different experimental conditions, and we studied gonadal morphology in five monthly samples taken after hatching. Significant sex-specific changes in gene expression (affecting about 25,000 genes) started around hatching. Gonads were still undifferentiated three weeks after hatching, but about half of the fish showed immature testes around seven weeks after hatching. Over the next few months, this phenotype was mostly replaced by the “testis-to-ovary” or “ovaries” phenotypes. The gonads of the remaining fish, i.e. approximately half of the fish in each sampling period, remained undifferentiated until six months after fertilization. Genetic sexing of the last two samples revealed that fish with undifferentiated gonads were all males, who, by that time, were on average larger than the genetic females (verified in 8-months old juveniles raised in another experiment). Only 12% of the genetic males showed testicular tissue six months after fertilization. We conclude that sex differentiation starts around hatching, goes through an all-male stage for both sexes (which represents a rare case of “undifferentiated” gonochoristic species that usually go through an all-female stage), and is delayed in males who, instead of developing their gonads, grow faster than females during these juvenile stages.Author contributionMRR and CW initiated the project. DM, OS, AU, LMC, LW, and CW sampled the adult fish, did the experimentalin vitrofertilizations, and prepared the embryos for experimental rearing in the laboratory. All further manipulations on the embryos and the larvae were done by DM, OS, AU, LMC, and LW. The RNA-seq data were analyzed by OS, JR, and MRR, the histological analyses were done by DM, supervised by SK, and the molecular genetic sexing was performed by DM, OS, AU, and KBM. DM, OS, and CW performed the remaining statistical analyses and wrote the first version of the manuscript that was then critically revised by all other authors.