Genetics and Evolution of Phenotypic Plasticity
01 Jan 1993-Annual Review of Ecology, Evolution, and Systematics (Annual Reviews 4139 El Camino Way, P.O. Box 10139, Palo Alto, CA 94303-0139, USA)-Vol. 24, Iss: 1, pp 35-68
TL;DR: Phenotypic plasticity is the change in the expressed phenotype of a genotype as a function of the environment, and is likely due both to differences in allelic expression across environments and to changes in interactions among loci.
Abstract: 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 thre...
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TL;DR: The existence of behavioral syndromes focuses the attention of behavioral ecologists on limited (less than optimal) behavioral plasticity and behavioral carryovers across situations, rather than on optimal plasticity in each isolated situation.
Abstract: Recent studies suggest that populations and species often exhibit behavioral syndromes; that is, suites of correlated behaviors across situations. An example is an aggression syndrome where some individuals are more aggressive, whereas others are less aggressive across a range of situations and contexts. The existence of behavioral syndromes focuses the attention of behavioral ecologists on limited (less than optimal) behavioral plasticity and behavioral carryovers across situations, rather than on optimal plasticity in each isolated situation. Behavioral syndromes can explain behaviors that appear strikingly non-adaptive in an isolated context (e.g. inappropriately high activity when predators are present, or excessive sexual cannibalism). Behavioral syndromes can also help to explain the maintenance of individual variation in behavioral types, a phenomenon that is ubiquitous, but often ignored. Recent studies suggest that the behavioral type of an individual, population or species can have important ecological and evolutionary implications, including major effects on species distributions, on the relative tendencies of species to be invasive or to respond well to environmental change, and on speciation rates. Although most studies of behavioral syndromes to date have focused on a few organisms, mainly in the laboratory, further work on other species, particularly in the field, should yield numerous new insights.
2,954 citations
Cites background from "Genetics and Evolution of Phenotypi..."
...Phenotypic plasticity is ‘the change in the expressed phenotype of a genotype as a function of the environment’ [ 62 ]....
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TL;DR: It is concluded that adaptive plasticity that places populations close enough to a new phenotypic optimum for directional selection to act is the only Plasticity that predictably enhances fitness and is most likely to facilitate adaptive evolution on ecological time-scales in new environments.
Abstract: Summary
1The role of phenotypic plasticity in evolution has historically been a contentious issue because of debate over whether plasticity shields genotypes from selection or generates novel opportunities for selection to act. Because plasticity encompasses diverse adaptive and non-adaptive responses to environmental variation, no single conceptual framework adequately predicts the diverse roles of plasticity in evolutionary change.
2Different types of phenotypic plasticity can uniquely contribute to adaptive evolution when populations are faced with new or altered environments. Adaptive plasticity should promote establishment and persistence in a new environment, but depending on how close the plastic response is to the new favoured phenotypic optimum dictates whether directional selection will cause adaptive divergence between populations. Further, non-adaptive plasticity in response to stressful environments can result in a mean phenotypic response being further away from the favoured optimum or alternatively increase the variance around the mean due to the expression of cryptic genetic variation. The expression of cryptic genetic variation can facilitate adaptive evolution if by chance it results in a fitter phenotype.
3We conclude that adaptive plasticity that places populations close enough to a new phenotypic optimum for directional selection to act is the only plasticity that predictably enhances fitness and is most likely to facilitate adaptive evolution on ecological time-scales in new environments. However, this type of plasticity is likely to be the product of past selection on variation that may have been initially non-adaptive.
4We end with suggestions on how future empirical studies can be designed to better test the importance of different kinds of plasticity to adaptive evolution.
2,417 citations
Cites background from "Genetics and Evolution of Phenotypi..."
...…production of plasticity are expressed (e.g. van Tienderen 1991, 1997; Moran 1992; DeWitt et al. 1998; Reylea 2002; Ernande & Dieckman 2004) and the degree of gene flow between populations distributed among different environments (e.g. Scheiner 1993; de Jong & Behera 2002; Sultan & Spencer 2002)....
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...Via & Lande 1985; Scheiner 1993, Via et al. 1995; de Jong 2005)....
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...Key-words : phenotypic plasticity, contemporary adaptation, genotype × environment interaction, adaptive divergence, genetic assimilation Functional Ecology (2007) 21 , 394–407 doi: 10.1111/j.1365-2435.2007.01283.x...
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TL;DR: The costs and limits of phenotypic plasticity are thought to have important ecological and evolutionary consequences, yet they are not as well understood as the benefits of plasticity.
Abstract: The costs and limits of phenotypic plasticity are thought to have important ecological and evolutionary consequences, yet they are not as well understood as the benefits of plasticity. At least nine ideas exist regarding how plasticity may be costly or limited, but these have rarely been discussed together. The most commonly discussed cost is that of maintaining the sensory and regulatory machinery needed for plasticity, which may require energy and material expenses. A frequently considered limit to the benefit of plasticity is that the environmental cues guiding plastic development can be unreliable. Such costs and limits have recently been included in theoretical models and, perhaps more importantly, relevant empirical studies now have emerged. Despite the current interest in costs and limits of plasticity, several lines of reasoning suggest that they might be difficult to demonstrate.
2,109 citations
TL;DR: It is suggested that behavioral syndromes could play a useful role as an integrative bridge between genetics, experience, neuroendocrine mechanisms, evolution, and ecology.
Abstract: A behavioral syndrome is a suite of correlated behaviors expressed either within a given behavioral context (e.g., correlations between foraging behaviors in different habitats) or across different contexts (e.g., correlations among feeding, antipredator, mating, aggressive, and dispersal behaviors). For example, some individuals (and genotypes) might be generally more aggressive, more active or bold, while others are generally less aggressive, active or bold. This phenomenon has been studied in detail in humans, some primates, laboratory rodents, and some domesticated animals, but has rarely been studied in other organisms, and rarely examined from an evolutionary or ecological perspective. Here, we present an integrative overview on the potential importance of behavioral syndromes in evolution and ecology. A central idea is that behavioral correlations generate tradeoffs; for example, an aggressive genotype might do well in situations where high aggression is favored, but might be inappropriate...
1,766 citations
TL;DR: Logistical difficulties preclude a detailed study of dispersal for many species, however incorporating unrealistic dispersal assumptions in spatial population models may yield inaccurate and costly predictions, and further studies are necessary to explore the importance of incorporating specific condition‐dependent dispersal strategies for evolutionary and population dynamic predictions.
Abstract: Knowledge of the ecological and evolutionary causes of dispersal can be crucial in understanding the behaviour of spatially structured populations, and predicting how species respond to environmental change. Despite the focus of much theoretical research, simplistic assumptions regarding the dispersal process are still made. Dispersal is usually regarded as an unconditional process although in many cases fitness gains of dispersal are dependent on environmental factors and individual state. Condition-dependent dispersal strategies will often be superior to unconditional, fixed strategies. In addition, dispersal is often collapsed into a single parameter, despite it being a process composed of three interdependent stages: emigration, inter-patch movement and immigration, each of which may display different condition dependencies. Empirical studies have investigated correlates of these stages, emigration in particular, providing evidence for the prevalence of conditional dispersal strategies. Ill-defined use of the term ‘dispersal’, for movement across many different spatial scales, further hinders making general conclusions and relating movement correlates to consequences at the population level. Logistical difficulties preclude a detailed study of dispersal for many species, however incorporating unrealistic dispersal assumptions in spatial population models may yield inaccurate and costly predictions. Further studies are necessary to explore the importance of incorporating specific condition-dependent dispersal strategies for evolutionary and population dynamic predictions.
1,637 citations
Cites background from "Genetics and Evolution of Phenotypi..."
...…future environmental conditions can be predicted on the basis of the current conditions, and so condition-dependent dispersal may evolve, with dispersal cueing on the environmental parameters correlating with patch quality (Scheiner, 1993; Danchin, Heg & Doligez, 2001; Doligez et al., 2003)....
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...When there is some autocorrelation, future environmental conditions can be predicted on the basis of the current conditions, and so condition-dependent dispersal may evolve, with dispersal cueing on the environmental parameters correlating with patch quality (Scheiner, 1993; Danchin, Heg & Doligez, 2001; Doligez et al., 2003)....
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...…unconditional strategy (for exceptions see Tables 1 and 2) though fixed strategies, insensitive to the environment, may only be expected when there are constraints on obtaining information on patch quality or when changes in habitat quality are unpredictable (Scheiner, 1993; Doligez et al., 2003)....
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...The majority of evolutionary and population models typically treat dispersal as a fixed, unconditional strategy (for exceptions see Tables 1 and 2) though fixed strategies, insensitive to the environment, may only be expected when there are constraints on obtaining information on patch quality or when changes in habitat quality are unpredictable (Scheiner, 1993; Doligez et al., 2003)....
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References
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TL;DR: In this article, age and size at maturity at maturity number and size of offspring Reproductive lifespan and ageing are discussed. But the authors focus on the effects of age and stage structure on fertility.
Abstract: Prologue Part I: Evolutionary explanation Demography: age and stage structure Quantitative genetics and reaction norms Trade-offs Lineage-specific effects Part II: Age and size at maturity Number and size of offspring Reproductive lifespan and ageing Appendices Glossary References Author index Subject index.
10,338 citations
TL;DR: Page 108, last line of text, for "P/P″" read "P′/ P″."
Abstract: Page 108, last line of text, for "P/P″" read "P′/P″."
Page 120, last line, for "δ v " read "δ y ."
Page 123, line 10, for "4Nn" read "4Nu."
Page 125, line 1, for "q" read "q."
Page 126, line 12, for "q" read "q."
Page 135, line 5 from bottom, for "y4Nsq" read "e4Nsq."
Page 141, lines 8
7,850 citations
TL;DR: Measures of directional and stabilizing selection on each of a set of phenotypically correlated characters are derived, retrospective, based on observed changes in the multivariate distribution of characters within a generation, not on the evolutionary response to selection.
Abstract: Natural selection acts on phenotypes, regardless of their genetic basis, and produces immediate phenotypic effects within a generation that can be measured without recourse to principles of heredity or evolution. In contrast, evolutionary response to selection, the genetic change that occurs from one generation to the next, does depend on genetic variation. Animal and plant breeders routinely distinguish phenotypic selection from evolutionary response to selection (Mayo, 1980; Falconer, 1981). Upon making this critical distinction, emphasized by Haldane (1954), precise methods can be formulated for the measurement of phenotypic natural selection. Correlations between characters seriously complicate the measurement of phenotypic selection, because selection on a particular trait produces not only a direct effect on the distribution of that trait in a population, but also produces indirect effects on the distribution of correlated characters. The problem of character correlations has been largely ignored in current methods for measuring natural selection on quantitative traits. Selection has usually been treated as if it acted only on single characters (e.g., Haldane, 1954; Van Valen, 1965a; O'Donald, 1968, 1970; reviewed by Johnson, 1976 Ch. 7). This is obviously a tremendous oversimplification, since natural selection acts on many characters simultaneously and phenotypic correlations between traits are ubiquitous. In an important but neglected paper, Pearson (1903) showed that multivariate statistics could be used to disentangle the direct and indirect effects of selection to determine which traits in a correlated ensemble are the focus of direct selection. Here we extend and generalize Pearson's major results. The purpose of this paper is to derive measures of directional and stabilizing (or disruptive) selection on each of a set of phenotypically correlated characters. The analysis is retrospective, based on observed changes in the multivariate distribution of characters within a generation, not on the evolutionary response to selection. Nevertheless, the measures we propose have a close connection with equations for evolutionary change. Many other commonly used measures of the intensity of selection (such as selective mortality, change in mean fitness, variance in fitness, or estimates of particular forms of fitness functions) have little predictive value in relation to evolutionary change in quantitative traits. To demonstrate the utility of our approach, we analyze selection on four morphological characters in a population of pentatomid bugs during a brief period of high mortality. We also summarize a multivariate selection analysis on nine morphological characters of house sparrows caught in a severe winter storm, using the classic data of Bumpus (1899). Direct observations and measurements of natural selection serve to clarify one of the major factors of evolution. Critiques of the "adaptationist program" (Lewontin, 1978; Gould and Lewontin, 1979) stress that adaptation and selection are often invoked without strong supporting evidence. We suggest quantitative measurements of selection as the best alternative to the fabrication of adaptive scenarios. Our optimism that measurement can replace rhetorical claims for adaptation and selection is founded in the growing success of field workers in their efforts to measure major components of fitness in natural populations (e.g., Thornhill, 1976; Howard, 1979; Downhower and Brown, 1980; Boag and Grant, 1981; Clutton-Brock et
4,990 citations
TL;DR: The model, Yij = μ1 + β1Ij + δij, defines stability parameters that may be used to describe the performance of a variety over a series of environments to see whether genetic differences could be detected.
Abstract: The model, Yij = μ1 + β1Ij + δij, defines stability parameters that may be used to describe the performance of a variety over a series of environments. Yij is the variety mean of the ith variety at the jth environment, µ1 is the ith variety mean over all environments, β1 is the regression coefficient that measures the response of the ith variety to varying environments, δij is the deviation from regression of the ith variety at the jth environment, and Ij is the environmental index.
The data from two single-cross diallels and a set of 3-way crosses were examined to see whether genetic differences could be detected. Genetic differences among lines were indicated for the regression of the lines on the environmental index with no evidence of nonadditive gene action. The estimates of the squared deviations from regression for many hybrids were near zero, whereas extremely large estimates were obtained for other hybrids.
3,754 citations