Search

Environments affect phenotypes through two elementary functions: modifying (by affecting the development of individuals' phenotypes) and adaptive (by determining the phenotypes' adaptive significance). Adaptation may be perceived to coordinate the two functions, which may even be performed by the same environmental factor. Organismic transformation of the environment can again affect both functions, where the adaptive functions are commonly addressed via notions of "niche/habitat construction" or "extended phenotype" and modifying function are largely ignored. The multi-causal role of these transformations in evolution and adaptation is hard to model and formalize using standard tools. To arrive at a more comprehensive representation, a systems approach is taken that allows classification and generalization of earlier results and the outlining of new insights. These include the following: ∗ Temporary transformation (restricted to one adaptational episode) is structurally equivalent to adaptation without transformation and therefore provide no new insights. ∗ Prolonged transformation (extending over several episodes) in either adaptive or modifying environments promotes adaptational coordination between the two functions but ultimately prevents persistent adaptedness. ∗ The success of transformations of the adaptive environment that do not affect the modifying environment depends on the diversity in the system states rather than on phenogenetic plasticity. ∗ A substantial difference between transformation of the adaptive and of the modifying environment is that adaptation can be reached within a single episode via transformation of the modifying environment, even if the adaptive environment has no modifying effect. The evolutionary consequences await explicit model analysis. ∗ Migration can be interpreted in terms of environmental transformation of either function, modifying or adaptive, by replacing transformation between environments by migration between them. Established results from migration models can help to reassess existing models of adaptation by environmental transformation and to design new models. [ABSTRACT FROM AUTHOR]

Modular colonial benthic organisms exhibit high phenotypic plasticity, which is considered an effective strategy when faced with fluctuations in abiotic and biotic factors. However, when environmental changes occur abruptly, organisms' adaptive capabilities can be limited, leading to the death of some colonies or to mass mortalities. Additionally, a decrease in body size has been proposed as one of the most common responses in both terrestrial and aquatic organisms to face global warming. Here, temperate corals' response to thermal stress was documented using the precious red coral Corallium rubrum as a model species. The increased frequency of marine heat waves recorded in the north-western Mediterranean has led to a decrease in the total number of colonies of the analysed populations and reduced colony size in those that have survived, likely through fragmentation and branch loss. The laboratory analyses carried out on collected fragments showed an unexpected swelling, similar to resorption. Additionally, the occurrence of regular sclerite-like protuberances, typical of a normal skeleton surface, suggested a regeneration process. The documented phenomenon supports the hypothesis that C. rubrum exhibits an adaptive behaviour via the autotomy of branches, providing it with an unexpected resilience against climate anomalies thanks to phenotypic plasticity. [ABSTRACT FROM AUTHOR]

Summary: Understanding constraints to phenotypic plasticity is key given its role on the response of organisms to environmental change. It has been suggested that phenotypic integration, the structure of trait covariation, could limit trait plasticity. However, the relationship between plasticity and integration is far from resolved.Using a database of functional plasticity to drought of a Mediterranean shrub that included 20 ecophysiological traits, we assessed environmentally‐induced changes in phenotypic integration and whether integration constrained the expression of plasticity, accounting for the within‐environment phenotypic variation of traits. Furthermore, we provide the first test of the association between differential trait plasticity and trait integration across an optimum and a stressful environment.Phenotypic plasticity was positively associated with phenotypic integration in both environments, but this relationship was lost when phenotypic variation was considered. The similarity in the plastic response of two traits predicted their integration across environments, with integrated traits having more similar plasticity. Such variation in the plasticity of traits partly explained the lower phenotypic integration found in the stressful environment.We found no evidence that integration may constitute an internal constraint to plasticity. Rather, we present the first empirical demonstration that differences in plastic responses may involve a major reorganization of the relationships among traits, and challenge the notion that stress generally induces a tighter phenotype. [ABSTRACT FROM AUTHOR]

Reproducibility in biomedical research, and more specifically in preclinical animal research, has been seriously questioned. Several cases of spectacular failures to replicate findings published in the primary scientific literature have led to a perceived reproducibility crisis. Diverse threats to reproducibility have been proposed, including lack of scientific rigour, low statistical power, publication bias, analytical flexibility and fraud. An important aspect that is generally overlooked is the lack of external validity caused by rigorous standardization of both the animals and the environment. Here, we argue that a reaction norm approach to phenotypic variation, acknowledging gene-by-environment interactions, can help us seeing reproducibility of animal experiments in a new light. We illustrate how dominating environmental effects can affect inference and effect size estimates of studies and how elimination of dominant factors through standardization affects the nature of the expected phenotype variation through the reaction norms of small effect. Finally, we discuss the consequences of reaction norms of small effect for statistical analysis, specifically for random effect latent variable models and the random lab model. [ABSTRACT FROM AUTHOR]

The investigation of morphological traits of main development cycles of Erysiphe palczewsk Takamatsuii on various host plant species at seven different ecological geo-points in Ukraine. Sampling was conducted with the help of plant route research method in the parks in Kiev and Kiev region, and also in Zhytomyr. Phytopathologic analysis, morphometry of conidia, fruit bodies and their appendages as well as asci and ascospores were carried out using a light microscope and a smartphone with the software "Magnifier Cam". The greatest disease development is manifested on the fruits (beans), leaves, branches of current annual accretion on Robinia pseudoacacía L. For the first time in Ukraine, all development stages of invasive species Erysiphe palczewskii were detected on black. locust (Robinia pseudoacacia L.). Comparative analysis of morphometric parameters of conidia, fruit bodies, appendages, asci and scospores from Caragana arborescens and black locust from different ecological geo-points was conducted. [ABSTRACT FROM AUTHOR]

Background and Aims Plants experiencing contrasting environmental conditions may accommodate such heterogeneity by expressing phenotypic plasticity, evolving local adaptation or a combination of both. We investigated patterns of genetic differentiation and plasticity in response to drought in populations of the gypsum specialist Lepidium subulatum. Methods We created an outdoor common garden with rain exclusion structures using 60 maternal progenies from four distinct populations that substantially differ in climatic conditions. We characterized fitness, life history and functional plasticity in response to two contrasting treatments that realistically reflect soil moisture variation in gypsum habitats. We also assessed neutral genetic variation and population structure using microsatellite markers. Key Results In response to water stress, plants from all populations flowered earlier, increased allocation to root tissues and advanced leaf senescence, consistent with a drought escape strategy. Remarkably, these probably adaptive responses were common to all populations, as shown by the lack of population × environment interaction for almost all functional traits. This generally common pattern of response was consistent with substantial neutral genetic variation and large differences in population trait means. However, such population-level trait variation was not related to climatic conditions at the sites of origin. Conclusions Our results show that, rather than ecotypes specialized to local climatic conditions, these populations are composed of highly plastic, general-purpose genotypes in relation to climatic heterogeneity. The strikingly similar patterns of plasticity among populations, despite substantial site of origin differences in climate, suggest past selection on a common norm of reaction due to similarly high levels of variation within sites. It is thus likely that plasticity will have a prevalent role in the response of this soil specialist to further environmental change. [ABSTRACT FROM AUTHOR]

Water limitation is a primary driver of plant geographic distributions and individual plant fitness. Drought resistance is the ability to survive and reproduce despite limited water, and numerous studies have explored its physiological basis in plants. However, it is unclear how drought resistance and trade-offs associated with drought resistance evolve within plant clades. We quantified the relationship between water availability and fitness for 13 short-lived plant taxa in the Streptanthus clade that vary in their phenology and the availability of water in the environments where they occur. We derived two parameters from these relationships: plant fitness when water is not limiting and the water inflection point (WIF), the watering level at which additional water is most efficiently turned into fitness. We used phylogenetic comparative methods to explore trade-offs related to drought resistance and trait plasticity and the degree to which water relationship parameters are conserved. Taxa from drier climates produced fruits at the lowest water levels, had a lower WIF, flowered earlier, had shorter life spans, had greater plastic water-use efficiency (WUE), and had lower fitness at nonlimiting water. In contrast, later-flowering Streptanthus taxa from less xeric climates experienced high fitness at nonlimiting water but had no fitness at the lowest water levels. Across the clade, we found a trade-off between drought resistance and fitness at high water, though a single ruderal species was an outlier in this relationship. Our results suggest that drought escape trades off with maximal fitness under nonlimiting water, and both are tied to phenology. We also found that variation in trait plasticity determines how different plant species produce fitness over a water gradient. [ABSTRACT FROM AUTHOR]

Labile plasticity in a complex quantitative character is modeled, with multiple components contributing to net plasticity in the character. Each component has a specific development rate, norm of reaction, and cost of plasticity. For example, thermal adaptation in mammals includes seasonal fat deposition and fur growth, short-term shivering and sweating or panting, and movement between warm and cold sites. Norms of reaction do not reveal patterns of developmental integration, which must be investigated by studies of developmental dynamics in a changing environment. In a periodic environment, a labile character with a single component of plasticity is constrained by filtering environmental frequencies above the development rate and by the cost of plasticity. With multiple components of plasticity, some patterns of integration can alleviate these constraints to greatly improve fidelity of the mean phenotype tracking multiperiodic cycles in the optimum phenotype. This occurs by environmental signal amplification or inhibition through developmental integration among components and by an augmented development rate of net plasticity in the character that reduces environmental frequency filtering. When development of a component with high cost of plasticity is regulated partly by the norm of reaction of another component, evolution can diminish the reaction norm slope of the costly component without curtailing its development, thereby reducing the loss of fitness from its cost of plasticity. Apparent maladaptation in a component of plasticity may be an integral part of an adaptive pattern of developmental integration by mutual inhibition between components and compensatory evolution of a negative component reaction norm slope. [ABSTRACT FROM AUTHOR]

The sexual phenotype of the gonad is dependent on incubation temperature in many turtles, all crocodilians, and some lepidosaurians. At hatching, identification of sexual phenotype is impossible without sacrificing the neonates. For this reason, a general method to infer sexual phenotype from incubation temperatures is needed. Temperature influences sex determination during a specific period of the embryonic development, starting when the gonad begins to form. At constant incubation temperatures, this thermosensitive period for sex determination (TSP) is located at the middle third of incubation duration (MTID). When temperature fluctuates, the position of the thermosensitive period for sex determination can be shifted from the MTID because embryo growth is affected by temperature. A method is proposed to locate the thermosensitive period for sex determination based on modelling the embryo growth, allowing its precise identification from a natural regime of temperatures. Results from natural nests and simulations show that the approximation of the thermosensitive period for sex determination to the middle third of incubation duration may create a quasi-systematic bias to lower temperatures when computing the average incubation temperature during this period and thus a male-bias for sex ratio estimate. [ABSTRACT FROM AUTHOR]

Adaptability to a variety of environmental conditions is a prominent feature of Homo sapiens. We hypothesize that this feature can be explained by evolutionary changes in gene promoters active in the brain prefrontal cortex leading to a more flexible gene regulation network. The genotype-dependent range of gene expression can be broader in humans than in other higher primates. Thus, we searched for specific signatures of evolutionary changes in promoter architectures of multiple hominid genes, including the genes active in human cortical neurons that may indicate an increase of variability of gene expression rather than just changes in the level of expression, such as downregulation or upregulation of the genes. We performed a whole-genome search for genetic-based alterations that may impact gene regulation “flexibility” in a process of hominids evolution, such as (i) CpG dinucleotide content, (ii) predicted nucleosome-DNA dissociation constant, and (iii) predicted affinities for TATA-binding protein (TBP) in gene promoters. We tested all putative promoter regions across the human genome and especially gene promoters in active chromatin state in neurons of prefrontal cortex, the brain region critical for abstract thinking and social and behavioral adaptation. Our data imply that the origin of modern man has been associated with an increase of flexibility of promoter-driven gene regulation in brain. In contrast, after splitting from the ancestral lineages of H. sapiens, the evolution of ape species is characterized by reduced flexibility of gene promoter functioning, underlying reduced variability of the gene expression. [ABSTRACT FROM AUTHOR]

The validity of the two-component structure of annuity curves in Drosophila melanogaster (line Canton-S) observed in our previous studies has been confirmed. The structure is formed by a combination of a stable five-phase pattern and the variability of phase duration (the latter determines the variability of insect viability). Both the stable and the variable component were preserved over 60 generations of flies. The unconventional type of variability addressed in the present study exists along with the well-known type of variability related to the stochastic variation of the annuity curves. The variance of viability that characterizes the reaction norm remains unchanged in a series of generations as well. Thus, both types of variability can be classified as genetically determined phenomena. [ABSTRACT FROM AUTHOR]

Extinction was recognized as a scientific fact 200 years ago, although no adequate paradigm has emerged to explain the process. Prevailing theory has focused on 'cause(s)' of extinction but has neglected 'effect' and 'mechanism'. These omissions preclude the formulation of a functional paradigm necessary for remedial action in response to the impending anthropogenic mediated, worldwide extinction crisis. The new paradigm is defined as the multi-generational, attritional loss of reproductive fitness. Stabilizing selection continuously adapts species to specific ecosystems, which often results in highly evolved species prone to extinction when environments shift. Some species survive by tracking the declining palaeoclimates in which they presumably evolved, often becoming relicts prior to extinction. Compelling new evidence shows that even mass extinctions are largely a result of environmental change leading to widespread, attritional reproductive decline, rather than a result of instantaneous global catastrophes. [ABSTRACT FROM AUTHOR]

Now the new high-quality policy directed on optimization of conformity of genetic features of grades to conditions of their cultivation is necessary. Use of a positive effect of this interaction under production conditions by carrying out of high-quality structure of wheat to concrete agro technological conditions, doesn't cause additional expenses for an intensification of technologies and variety replacement, but capable to lift productivity in economy to 25 %.

The introduced Asian plant Polygonum cespitosum has only recently become invasive in northeastern North America, spreading into sunny as well as shaded habitats. We present findings from a multiyear case study of this ongoing species invasion, drawing on field environmental measurements, glasshouse plasticity and resurrection experiments, and molecular genetic (microsatellite) data. We focus in particular on patterns of individual phenotypic plasticity (norms of reaction), their diversity within and among populations in the species' introduced range, and their contribution to its potential to evolve even greater invasiveness. Genotypes from introduced-range P. cespitosum populations have recently evolved to express greater adaptive plasticity to full sun and/or dry conditions without any loss of fitness in shade. Evidently, this species may evolve the sort of 'general-purpose genotypes' hypothesized by Herbert Baker to characterize an 'ideal weed.' Indeed, we identified certain genotypes capable of extremely high reproductive output across contrasting conditions, including sunny, shaded, moist, and dry. Populations containing these high-performance genotypes had consistently higher fitness in all glasshouse habitats; there was no evidence for local adaptive differentiation among populations from sunny, shaded, moist, or dry sites. Norm of reaction data may provide valuable insights to invasion biology: the presence of broadly adaptive, high-performance genotypes can promote a species' ecological spread while providing the fuel for increased invasiveness to evolve. [ABSTRACT FROM AUTHOR]

Species level identification of octocorals is often based on the form of skeletal elements, the sclerites. Morphological variation in sclerites across and within habitats complicates both species delineation and the identification of specimens, both of which are essential for characterizing and understanding octocoral diversity. In order to quantify the effects of environmental plasticity on sclerite morphology, branches from the Caribbean gorgonian Antillogorgia bipinnata were removed from colonies at depths of 18 and 23 m and reciprocally transplanted between those sites and transplanted to an 8 m depth site for 7 months. Images of sclerites from those colonies were compared using elliptical Fourier analyses (EFA) of the sclerite outline. The length of scaphoids produced after transplantation was larger than those in older tissue, suggesting length was affected by the process of transplantation. Shape of scaphoids as detected in the EFA, differed between sites, and the reciprocal crosses suggest some of the difference was a plastic response to the environment. The results demonstrate the presence of some environmental plasticity in sclerite form. However, while detectable using EFA, the differences in form were not apparent in microscopical observations of the sclerites and thus would not affect identification of specimens nor traditional species delineation. [ABSTRACT FROM AUTHOR]

Adaptive responses to autocorrelated environmental fluctuations through evolution in mean reaction norm elevation and slope and an independent component of the phenotypic variance are analyzed using a quantitative genetic model. Analytic approximations expressing the mutual dependencies between all three response modes are derived and solved for the joint evolutionary outcome. Both genetic evolution in reaction norm elevation and plasticity are favored by slow temporal fluctuations, with plasticity, in the absence of microenvironmental variability, being the dominant evolutionary outcome for reasonable parameter values. For fast fluctuations, tracking of the optimal phenotype through genetic evolution and plasticity is limited. If residual fluctuations in the optimal phenotype are large and stabilizing selection is strong, selection then acts to increase the phenotypic variance (bet-hedging adaptive). Otherwise, canalizing selection occurs. If the phenotypic variance increases with plasticity through the effect of microenvironmental variability, this shifts the joint evolutionary balance away from plasticity in favor of genetic evolution. If microenvironmental deviations experienced by each individual at the time of development and selection are correlated, however, more plasticity evolves. The adaptive significance of evolutionary fluctuations in plasticity and the phenotypic variance, transient evolution, and the validity of the analytic approximations are investigated using simulations. [ABSTRACT FROM AUTHOR]

Genes and environment make the organism. Darwin stood firm in his denial of any direct role of environment in the modification of heredity. His theory of evolution heralded two debates: one about the importance and adequacy of natural selection as the main mechanism of evolution, and the other about the role of genes versus environment in the modification of phenotype and evolution. Here, I provide an overview of the second debate and show that the reasons for the gene versus environment battle were twofold: first, there was confusion about the role of environment in modifying the inheritance of a trait versus the evolution of that trait, and second, there was misunderstanding about the meaning of environment and its interaction with genes in the production of phenotypes. It took nearly a century to see that environment does not directly affect the inheritance of a phenotype (i.e., its heredity), but it is nevertheless the primary mover of phenotypic evolution. Effects of genes and environment are not separate but interdependent. One cannot separate the effect of genes from that of environment, or nature from nurture. To answer the question posed in the title, it is partly because the 20th century has been a century of unending progress in genetics. But also because unlike physics, biology is not colorblind; progress in biology has often been delayed beyond the Kuhnian paradigm change due to built-in interest in negating the influence of environment. Those who are against evolution, of course, cannot be expected to understand the role of environment in evolution. Those for it, many biologists included, believing in the supremacy of genes empowers them by giving adaptation a solely gene-directed (self-driven) 'teleological' interpretation. [ABSTRACT FROM AUTHOR]

Copyright of Genome is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The incubation of eggs is strongly influenced by temperature as observed in all species studied to date. For example, incubation duration, sexual phenotype, growth, and performances in many vertebrate hatchlings are affected by incubation temperature. Yet it is very difficult to predict temperature effect based on the temperature within a field nest, as temperature varies throughout incubation. Previous works used egg incubation at constant temperatures in the laboratory to evaluate the dependency of growtProd. Type: FTPh rate on temperature. However, generating such data is time consuming and not always feasible due to logistical and legislative constraints. This paper therefore presents a methodology to extract the thermal reaction norm for the embryo growth rate directly from a time series of incubation temperatures recorded within natural nests. This methodology was successfully applied to the nests of the marine turtle Caretta caretta incubated on Dalyan Beach in Turkey, although it can also be used for any egg-laying species, with some of its limitations being discussed in the paper. Knowledge about embryo growth patterns is also important when determining the thermosensitive period for species with temperature-dependent sex determination. Indeed, in this case, sexual phenotype is sensitive to temperature only during this window of embryonic development. [ABSTRACT FROM AUTHOR]

Quantitative genetic models of evolution of phenotypic plasticity are used to derive environmental tolerance curves for a population in a changing environment, providing a theoretical foundation for integrating physiological and community ecology with evolutionary genetics of plasticity and norms of reaction. Plasticity is modelled for a labile quantitative character undergoing continuous reversible development and selection in a fluctuating environment. If there is no cost of plasticity, a labile character evolves expected plasticity equalling the slope of the optimal phenotype as a function of the environment. This contrasts with previous theory for plasticity influenced by the environment at a critical stage of early development determining a constant adult phenotype on which selection acts, for which the expected plasticity is reduced by the environmental predictability over the discrete time lag between development and selection. With a cost of plasticity in a labile character, the expected plasticity depends on the cost and on the environmental variance and predictability averaged over the continuous developmental time lag. Environmental tolerance curves derived from this model confirm traditional assumptions in physiological ecology and provide new insights. Tolerance curve width increases with larger environmental variance, but can only evolve within a limited range. The strength of the trade-off between tolerance curve height and width depends on the cost of plasticity. Asymmetric tolerance curves caused by male sterility at high temperature are illustrated. A simple condition is given for a large transient increase in plasticity and tolerance curve width following a sudden change in average environment. [ABSTRACT FROM AUTHOR]

Background and Aims Herbivory and plant defence differ markedly among seedlings and juvenile and mature plants in most species. While ontogenetic patterns of chemical resistance have been the focus of much research, comparatively little is known about how tolerance to damage changes across ontogeny. Due to dramatic shifts in plant size, resource acquisition, stored reserves and growth, it was predicted that tolerance and related underlying mechanisms would differ among ontogenetic stages. Methods Ontogenetic patterns in the mechanisms of tolerance were investigated in Plantago lanceolata and P. major (Plantaginaceae) using the genetic sib-ship approach. Pot-grown plants were subjected to 50 % defoliation at the seedling, juvenile and mature stages and either harvested in the short-term to look at plasticity in growth and photosynthesis in response to damage or allowed to grow through seed maturation to measure phenology, shoot compensation and reproductive fitness. Key Results Tolerance to defoliation was high in P. lanceolata, but low in P. major, and did not vary among ontogenetic stages in either species. Mechanisms underlying tolerance did vary across ontogeny. In P. lanceolata, tolerance was significantly related to flowering (juveniles) and pre-damage shoot biomass (mature plants). In P. major, tolerance was significantly related to pre-damage root biomass (seedlings) and induction of non-photochemical quenching, a photosynthetic parameter (juveniles). Conclusions Biomass partitioning was very plastic in response to damage and showed associations with tolerance in both species, indicating a strong role in plant defence. In contrast, photosynthesis and phenology showed weaker responses to damage and were related to tolerance only in certain ontogenetic stages. This study highlights the pivotal role of ontogeny in plant defence and herbivory. Additional studies in more species are needed to determine how seedlings tolerate herbivory in general and whether mechanisms vary across ontogeny in consistent patterns. [ABSTRACT FROM AUTHOR]

Rapid climate change both imposes strong selective pressures on natural populations - potentially reducing their growth rate and causing genetic evolution - and affects the physiology and development of individual organisms. Understanding and predicting the fates of populations under global change, including extinctions and geographical range shifts, requires analysing the interplay of these processes, which has long been a grey area in evolutionary biology., We review recent theory on the interaction of phenotypic plasticity, genetic evolution and demography in environments that change in time or space. We then discuss the main limitations of the models and the difficulties in testing theoretical predictions in the wild, notably regarding changes in phenotypic selection, the evolution of (co)variances of reaction norm parameters, and transient dynamics., We use two landmark examples of physiological responses to climate change -trees facing drier climate and extreme temperatures, and marine phytoplankton under rising CO2 - to highlight relatively neglected questions and indicate the theoretical and empirical challenges that they raise. These examples illustrate notably that age-specific patterns of plasticity and selection on the one hand, and changes in community interactions and functioning on the other hand, need to be further investigated theoretically and empirically for a better understanding of evolutionary demographic responses to climate change in the wild. [ABSTRACT FROM AUTHOR]

Behavioural phenotypes are invariably plastic to some degree and are among the most labile of phenotypes. Some are acquired over the course of development in a particular environment (developmental plasticity), but most are elicited by an environmental trigger and are expressed only briefly, but often repeatedly, in the life of an organism (activational plasticity). Thus, individuals can possess the ability to perform a behaviour, but in the absence of the appropriate environmental stimulus, can fail to do so over the course of a lifetime. Rarely is the evolution of behavioural phenotypes explored in the larger context of the evolution of phenotypically plastic traits. Here I argue that the evolution of behavioural phenotypes, regardless of the nature of the plasticity expressed, can be examined in the same way as the evolution of other plastic traits. I first provide a conceptual review of the factors that can influence the evolution of plastic phenotypes and of the ways in which behavioural plasticity can influence the evolution of other aspects of phenotype. Many of the most compelling questions involve contrasting ancestral patterns of plasticity with those in derived populations or species, a particularly challenging problem in the case of phenotypic plasticity. I therefore provide an overview of the ways in which the influence of plasticity upon evolution can be addressed and then provide a review of examples from the literature that offer initial insights into the role of behavioural plasticity in evolution. The questions are exciting, the data limited, and, as I argue in closing, we need creative insights into the ways in which behavioural plasticity has evolved and has in turn influenced the evolution of other aspects of phenotype. [ABSTRACT FROM AUTHOR]

Many behaviours vary in response to the environment (biotic or abiotic) and therefore represent an interesting form of phenotypic plasticity. Behavioural plasticity, like other plastic traits, can evolve through genetic assimilation or accommodation. However, little is known about the nature of changes in gene expression plasticity that accompanies these evolutionary changes in phenotypic plasticity. We know that variation in gene expression level, a first-order phenotype, underlies much behavioural variation. Several studies have begun to document which genes show expression-level variation related to plastic changes in behaviour as well as evolved changes in behaviour. Advances in sequencing technology allow us to address these questions on a genomic scale. By characterizing changes in gene expression according to the concept of a norm of reaction one can describe the evolved patterns of gene expression that accompany the evolution of behavioural plasticity. Here, we describe how genomic approaches can help us understand changes in gene expression that accompany or underlie the evolution of behavioural plasticity. To do this, we provide a framework of classification for the evolved patterns of gene expression plasticity that could underlie genetic assimilation or accommodation of behaviour. We provide examples of genetic assimilation from the animal behaviour and animal physiology literature that have been, or can be, studied at a genomic level. We then describe the characteristics of an appropriate study system and briefly address experimental design using the available genomic tools in a comparative context. Studying the patterns of gene expression associated with genetic assimilation will elucidate processes by which behavioural plasticity has evolved. [ABSTRACT FROM AUTHOR]

Adaptation to a sudden extreme change in environment, beyond the usual range of background environmental fluctuations, is analysed using a quantitative genetic model of phenotypic plasticity. Generations are discrete, with time lag τ between a critical period for environmental influence on individual development and natural selection on adult phenotypes. The optimum phenotype, and genotypic norms of reaction, are linear functions of the environment. Reaction norm elevation and slope (plasticity) vary among genotypes. Initially, in the average background environment, the character is canalized with minimum genetic and phenotypic variance, and no correlation between reaction norm elevation and slope. The optimal plasticity is proportional to the predictability of environmental fluctuations over time lag τ. During the first generation in the new environment the mean fitness suddenly drops and the mean phenotype jumps towards the new optimum phenotype by plasticity. Subsequent adaptation occurs in two phases. Rapid evolution of increased plasticity allows the mean phenotype to closely approach the new optimum. The new phenotype then undergoes slow genetic assimilation, with reduction in plasticity compensated by genetic evolution of reaction norm elevation in the original environment. [ABSTRACT FROM AUTHOR]

This article illustrates in which sense genetic determinism is still part of the contemporary interactionist consensus in medicine. Three dimensions of this consensus are discussed: kinds of causes, a continuum of traits ranging from monogenetic diseases to car accidents, and different kinds of determination due to different norms of reaction. On this basis, this article explicates in which sense the interactionist consensus presupposes the innate–acquired distinction. After a descriptive Part 1, Part 2 reviews why the innate–acquired distinction is under attack in contemporary philosophy of biology. Three arguments are then presented to provide a limited and pragmatic defense of the distinction: an epistemic, a conceptual, and a historical argument. If interpreted in a certain manner, and if the pragmatic goals of prevention and treatment (ideally specifying what medicine and health care is all about) are taken into account, then the innate–acquired distinction can be a useful epistemic tool. It can help, first, to understand that genetic determination does not mean fatalism, and, second, to maintain a system of checks and balances in the continuing nature–nurture debates. [ABSTRACT FROM AUTHOR]

Abstract: Traditional, quantitative behavioral geneticists and developmental psychobiologists such as Gilbert Gottlieb have long debated what it would take to create a truly developmental behavioral genetics. These disputes have proven so intractable that disputants have repeatedly suggested that the problem rests on their opponents’ conceptual confusion; whilst others have argued that the intractability results from the non-scientific, political motivations of their opponents. The authors provide a different explanation of the intractability of these debates. They show that the disputants have competing interpretations of the concepts of reaction norm, genotype–environment interaction, and gene. The common thread that underlies each of these disagreements, the authors argue, is the relevance of potential variation that is not manifest in any actual population to the understanding of development. [Copyright &y& Elsevier]

As the evolutionary importance of plant tolerance of herbivory is increasingly appreciated, more and more studies are not just measuring a plant's tolerance, but are comparing tolerance among plant genotypes, populations, species, and environments. Here, we suggest that caution must be taken in such comparative studies in the choice of measurement scales (and data transformations) for damage levels and plant performance. We demonstrate with a simple scenario of two plant groups of equal tolerance how the choice of scales can lead one to infer that the first group is more tolerant, the second group is more tolerant, or the two groups are equally tolerant—using the identical dataset. We conclude that to make reliable, logically consistent inferences when comparing tolerances among groups of plants, damage and performance should both be on an additive scale or both on a multiplicative scale. [ABSTRACT FROM AUTHOR]

Abstract: Major cardiovascular diseases arise as consequences of a reduced blood flow to oxygen consuming organs such as the brain and the heart. Their incidence and consequences increase with ageing and inappropriate nutrition conditions. In this study we compared the responses of young (1day old) or aged (1month old) Drosophila to dietary restriction and chronic hypoxia. Changing the two major diet components (sucrose and yeast) had complex and non linear consequences on longevity. Ageing and hypoxia completely remodelled the longevity/nutrient reaction norm. Aged flies required more sucrose and less yeast than young flies and became insensitive to dietary restriction by food dilution. The responses to chronic hypoxia were largely age independent and strongly diet dependent. For instance rich diets sensitized Drosophila to chronic hypoxia and hypoxia increased the life span of starving flies (aged or young). The results highlight the importance of nutrition conditions when assessing ageing and hypoxic tolerance in the Drosophila system. [Copyright &y& Elsevier]

1 Global change and emerging concepts in ecology and evolution are leading to a growing interest in phenotypic plasticity (PP), the environmentally contingent trait expression observed in a given genotype. The need to quantify PP in a simple manner in comparative ecological studies has resulted in the prevalence of various indices instead of the classic approaches, i.e. a comparison of slopes in the norms of reactions (trait vs. environment plots). 2 The objectives of this study were: (i) to review the most common methods for quantitative estimation of PP; (ii) to apply them to a specific case study of growth and shoot–root allocation responses to irradiance in seedlings of four woody species grown at 1%, 6%, 20% and 100% full sunlight; and (iii) to propose new methods of estimating PP. 3 The 17 different plasticity indices analysed rendered disparate results, with cross-overs in species PP rankings. Statistical comparisons of PP among species were not possible with most of the indices due to the lack of confidence intervals. The non-linear responses of the traits made the use of the slope of the reaction norm to quantify PP unrealistic, and raised awareness on values derived from studies that consider just two environments. 4 We propose an alternative approach to quantify PP based on phenotypic distances among individuals of a given species exposed to different environments, which is summarized in a relative distance plasticity index (RDPI) that allows for statistical comparisons of PP between species (or populations within species). RDPI was significantly correlated with 12 out of the 17 PP indices analysed. An index including the environmental range leading to the different phenotypes (environmentally standardized plasticity index, ESPI), and thus expressing plasticity per unit of environmental change, is also proposed. 5 The new indexes can statistically segregate and unambiguously rank species according to their PP, which can foster a better understanding of plant ecology and evolution, particularly when common protocols are used by different investigators. [ABSTRACT FROM AUTHOR]

Variation in fitness generated by differences in functional performance can often be traced to morphological variation among individuals within natural populations. However, morphological variation itself is strongly influenced by environmental factors (e.g., temperature) and maternal effects (e.g., variation in egg size). Understanding the full ecological context of individual variation and natural selection therefore requires an integrated view of how the interaction between the environment and development structures differences in morphology, performance, and fitness. Here we use naturally occurring environmental and maternal variation in the frog Bombina orientalis in South Korea to show that ovum size, average temperature, and variance in temperature during the early developmental period affect body sizes, shapes, locomotor performance, and ultimately the probability of an individual surviving interspecific predation in predictable but nonadditive ways. Specifically, environmental variability can significantly change the relationship between maternal investment in offspring and offspring fitness so that increased maternal investment can actually negatively affect offspring over a broad range of environments. Integrating environmental variation and developmental processes into traditional approaches of studying phenotypic variation and natural selection is likely to provide a more complete picture of the ecological context of evolutionary change. [ABSTRACT FROM AUTHOR]

Abstract: We investigated differences in response capacities among genotypes of six populations of Calamagrostis epigejos across three levels of soil fertility. Substrate effects were highly significant (P <0.001) for all characters (total biomass, root biomass, rhizome biomass, shoot biomass, root allocation, rhizome allocation, shoot allocation, vegetative tiller number, plant height, leaf-blade length, leaf width), indicating a high amount of plasticity. Population effects were highly significant (P ≤0.001) for all characters, except for leaf width and shoot allocation. There were also significant genotype effects for most characters as well as genotype-environment interactions. Plastic responses of most characters were correlated to each other, indicating a high degree of phenotypic integration. Root allocation was negatively correlated with rhizome allocation, revealing an inversely related allocation pattern between roots and rhizomes. Rhizome biomass was the character with the highest mean amount of plasticity over all populations (mean CV: 48.7±13.6), whereas leaf width showed lowest plasticity with a mean CV of 9.0±4.6. Character means and CVs over the six populations were not correlated, except root allocation and plant height. It was striking that the population from the most stressful habitat (a copper smelter) showed the lowest amount of plasticity. The great success of C. epigejos over a variety of contrasting habitats is due to both a high degree of phenotypic plasticity of individual genotypes and a considerable amount of genotypic variability within populations. [Copyright &y& Elsevier]

Abstract: Norms of reaction (NoRs) represent the phenotypic values of genotypes as functions of environmental parameters and permit the visualization of differences in phenotypic response of different genotypes. NoR graphs can be used to analyze interactions between genotypic and environmental factors during development to produce phenotypes in inbred strains of rats and mice. We describe the main features of NoRs, the history of their use in this context, and discuss several applications in behavioral neuroscience. In addition, we give a test for determining whether distinct strains have different NoRs. [Copyright &y& Elsevier]

In colonizing species, high phenotypic plasticity can contribute to survival and propagation in heterogenous adventive environments, and it has been suggested as a predictor of invasiveness. Observation of natural populations of an invasive species, Lythrum salicaria salicaria, indicated extensive variation in its growth and reproductive traits. Phenotypic plasticity of different life history traits of L salicaria was investigated using vegetative clones of each of 12 genotypes from one population in Ontario, Canada. We chose soil moisture as the treatment factor because of its importance in wetland species and raised all 12 genotypes in each of four soil moisture treatments. We examined an array of vegetative and reproductive traits, including root and shoot mass, shoot and inflorescence length, total seed set, floral mass, and morphometric variables. All observed vegetative as well as reproductive traits demonstrated significant phenotypic plasticity in response to soil moisture treatment. Even the stigma-anther separation involved significant genotype by environment interactions, suggesting that soil moisture may modify the relative positions of anthers and stigma. Compared to vegetative traits, most reproductive traits demonstrated crossing reaction norms, implying that the average differences in those traits among genotypes vary with the environment maintaining the genetic variation in a population. [ABSTRACT FROM AUTHOR]

Morphological parameters of Festuca rubra clones and their response to differences in the red/far red ratio (R : FR) were investigated in a growth chamber experiment. The twenty-four clones tested came from 15 micro-sites in three neighbouring meadow communities in the Krkonoše Mts. (Czech Republic). The community types were characterized by different canopy height and structure, and by different radiation conditions (relative R : FR) within the canopies. Low R : FR treatment resulted in reduced tillering and stimulated shoot elongation in most of the clones. In some clones, low R : FR ratios stimulated extravaginal tillering and rhizome system formation. The origin of the clones (i.e., community type) explained a part of variation in morphological parameters, but did not explain variation in the response to R : FR levels. Evidence for a consistent relationship between clone performance and radiation environment in the micro-sites from where the clones originated was not found. It seems that there is only limited selection of F. rubra clones (ecotypes) specialized for particular community types and no selection of clones specialized for particular micro-sites within communities. [ABSTRACT FROM AUTHOR]

Molecular reductionism has permeated all of biology and because of successive new technical breakthroughs it has succeeded in unraveling the structural details of genes and genomes. The molecular revolution has reached its reductionist limit, i.e., the study of component parts in isolation, and is ready to come full circle through genomics, proteomics, and gene expression studies back to the phenotype and bring evolutionary biology to confront the Darwinian paradigm, the relationship between gene, organism, and environment. Classical experimental population genetics, dealing with genetic polymorphism and estimation of selection coefficients on a gene-by-gene basis, is coming to an end and a new era of interdisciplinary and interactive biology focusing on dynamic relationships among gene, organism, and environment has begun. In the new population genetics, there will be a shift in focus from single genes to gene networks, from gene-structure to gene-regulation, from additivity to epistasis, and from simple phenotypes to gene-interaction networks and the evolution of complex and modular systems. [ABSTRACT FROM AUTHOR]

Variations on the norm of reaction among ten natural lodgepole pine populations sampled from three lodgepole pine subspecies (Pinus contorta ssp. contorta, ssp. latifolia and ssp. murrayana) were studied by using 20 year heights measured in 57 provenance test sites across interior British Columbia (B.C.). There were significant population by site interactions. Concurrent joint regression and the AMMI model were used to dissect these population by environmental interactions. Joint regression analysis indicated that three populations (from the northwest) had a negative linear regression coefficient with environmental deviation, three (from central and southeast sites) had a positive regression coefficient and four (from the southwest) had a zero regression coefficient. The AMMI model revealed a similar pattern of reaction norm among the ten populations. But the three significant IPCA axes, which captured twice as much of the G × E sum of squares than joint regression, were more effective in separating the ten populations and associating their performance with the climate of test sites and their origin. The variation patterns of reaction norm in lodgepole pine populations demonstrated that adaptation of lodgepole pine natural populations to the various physical environments, at sub-species as well as at population level, was due largely to a balance between selection for high growth potential in less severe environments and selection for high cold hardiness in severe environments. [ABSTRACT FROM AUTHOR]

To achieve a coherent evolutionary theory, it is necessary to account for the effects of the environment on the process of development. Phenotypic plasticity is the change in the expressed phenotype of a genotype as a function of the environment. Various measures of plasticity exist, many of which can be united within the framework of a polynomial function. This function is the norm of reaction. For the special case of a linear reaction norm, genetic variation can be partitioned into portions that are independent and dependent on the environment. From this partition two heritability measures are derived which can be used, alternatively, to compare populations or make predictions about the response to selection. Genetically, plasticity is likely due both to differences in allelic expression across environments and to changes in interactions among loci; plasticity is not a function of heterozygosity. Plasticity responds to both artificial and natural selection. The evolution of plasticity is modeled in three ways: optimality models, quantitative genetic models, and gametic models. All models make similar predictions about the conditions that will favor plasticity. In need of further development are the extension of quantitative genetic models, and structured population models; also needed are data on the true shapes of reaction norms and genetic variation and covariation for nonlinear reaction norm parameters and multiple environments. [ABSTRACT FROM AUTHOR]