scholarly journals Most published selection gradients are underestimated: Why this is and how to fix it

Evolution ◽  
2021 ◽  
Author(s):  
Niels Dingemanse ◽  
Yimen Gerardo Araya‐Ajoy ◽  
David F. Westneat
Keyword(s):  
Selection Gradients

Genetic control of kraft pulp yield in Eucalyptus globulus

2010 ◽  
Vol 40 (5) ◽  
pp. 917-927 ◽  
Author(s):  
Desmond J. Stackpole ◽  
René E. Vaillancourt ◽  
Geoffrey M. Downes ◽  
Christopher E. Harwood ◽  
Brad M. Potts
Keyword(s):  
Genetic Control ◽  
Eucalyptus Globulus ◽  
Kraft Pulp ◽  
Near Infrared ◽  
Genetic Correlations ◽  
Basic Density ◽  
Pulp Yield ◽  
Narrow Sense Heritability ◽  
Selection Gradients ◽  
Economic Worth

Pulp yield is an important breeding objective for Eucalyptus globulus Labill., but evaluation of its genetic control and genetic correlations with other traits has been limited by its high assessment cost. We used near infrared spectroscopy to study genetic variation in pulp yield and other traits in a 16-year-old E. globulus trial. Pulp yield was predicted for 2165 trees from 467 open-pollinated families from 17 geographic subraces. Significant differences between subraces and between families within subraces were detected for all traits. The high pulp yield of southern Tasmanian subraces suggested that their economic worth was previously underestimated. The narrow-sense heritability of pulp yield was medium (0.40). The significant positive genetic correlation between pulp yield and diameter (0.52) was at odds with the generally neutral values reported. The average of the reported genetic correlations between pulp yield and basic density (0.50) was also at odds with our nonsignificant estimate. Pulp yield of the subraces increased with increasing latitude, producing a negative correlation with density (–0.58). The absence of genetic correlations within subraces between pulp yield and density suggests that the correlation may be an independent response of the two traits to the same or different selection gradients that vary with latitude.

The Additive Partitioning of Selection Gradients

Evolution ◽  
1989 ◽  
Vol 43 (7) ◽  
pp. 1567 ◽  
Author(s):  
Michael J. Wade ◽  
Susan Kalisz
Keyword(s):  
Additive Partitioning ◽  
Selection Gradients

scholarly journals Evolution of a predator-induced, nonlinear reaction norm

2017 ◽  
Vol 284 (1861) ◽  
pp. 20170859 ◽  
Author(s):  
Mauricio J. Carter ◽  
Martin I. Lind ◽  
Stuart R. Dennis ◽  
William Hentley ◽  
Andrew P. Beckerman
Keyword(s):  
Evolutionary Dynamics ◽  
Daphnia Pulex ◽  
Reaction Norm ◽  
Maximum Response ◽  
Selective Predation ◽  
Evolutionary Trajectory ◽  
Defensive Reaction ◽  
Selection Gradients ◽  
Hunting Strategies ◽  
Evolutionary Response

Inducible, anti-predator traits are a classic example of phenotypic plasticity. Their evolutionary dynamics depend on their genetic basis, the historical pattern of predation risk that populations have experienced and current selection gradients. When populations experience predators with contrasting hunting strategies and size preferences, theory suggests contrasting micro-evolutionary responses to selection. Daphnia pulex is an ideal species to explore the micro-evolutionary response of anti-predator traits because they face heterogeneous predation regimes, sometimes experiencing only invertebrate midge predators and other times experiencing vertebrate fish and invertebrate midge predators. We explored plausible patterns of adaptive evolution of a predator-induced morphological reaction norm. We combined estimates of selection gradients that characterize the various habitats that D. pulex experiences with detail on the quantitative genetic architecture of inducible morphological defences. Our data reveal a fine scale description of daphnid defensive reaction norms, and a strong covariance between the sensitivity to cues and the maximum response to cues. By analysing the response of the reaction norm to plausible, predator-specific selection gradients, we show how in the context of this covariance, micro-evolution may be more uniform than predicted from size-selective predation theory. Our results show how covariance between the sensitivity to cues and the maximum response to cues for morphological defence can shape the evolutionary trajectory of predator-induced defences in D. pulex .

Integrating genomics and multivariate evolutionary quantitative genetics: a case study of constraints on sexual selection in Drosophila serrata

2021 ◽  
Vol 288 (1960) ◽  
Author(s):  
Adam J. Reddiex ◽  
Stephen F. Chenoweth
Keyword(s):  
Sexual Selection ◽  
Quantitative Genetics ◽  
Genome Wide Association Study ◽  
Mutational Bias ◽  
Stabilizing Selection ◽  
Genetic Constraints ◽  
Selection Gradients ◽  
Selection Responses ◽  
Drosophila Serrata ◽  
Potential Factors

In evolutionary quantitative genetics, the genetic variance–covariance matrix, G , and the vector of directional selection gradients, β , are key parameters for predicting multivariate selection responses and genetic constraints. Historically, investigations of G and β have not overlapped with those dissecting the genetic basis of quantitative traits. Thus, it remains unknown whether these parameters reflect pleiotropic effects at individual loci. Here, we integrate multivariate genome-wide association study (GWAS) with G and β estimation in a well-studied system of multivariate constraint: sexual selection on male cuticular hydrocarbons (CHCs) in Drosophila serrata . In a panel of wild-derived re-sequenced lines, we augment genome-based restricted maximum likelihood to estimate G alongside multivariate single nucleotide polymorphism (SNP) effects, detecting 532 significant associations from 1 652 276 SNPs. Constraint was evident, with β lying in a direction of G with low evolvability. Interestingly, minor frequency alleles typically increased male CHC-attractiveness suggesting opposing natural selection on β . SNP effects were significantly misaligned with the major eigenvector of G , g max , but well aligned to the second and third eigenvectors g 2 and g 3 . We discuss potential factors leading to these varied results including multivariate stabilizing selection and mutational bias. Our framework may be useful as researchers increasingly access genomic methods to study multivariate selection responses in wild populations.

scholarly journals Bee-Mediated Selection Favors Floral Sex Specialization in a Heterantherous Species: Strategies to Solve the Pollen Dilemma

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1685
Author(s):  
Larissa C. Oliveira ◽  
Alberto L. Teixido ◽  
Renata Trevizan ◽  
Vinícius L. G. Brito
Keyword(s):  
Floral Morphology ◽  
Pollen Dispersal ◽  
Fitness Components ◽  
Selection Gradients ◽  
Selective Pressures ◽  
Pollen Removal ◽  
Broad Variation ◽  
Phenotypic Gender ◽  
Pollen Flowers ◽  
Two Populations

Animal-pollinated plants show a broad variation in floral morphology traits and gametophyte production within populations. Thus, floral traits related to plant reproduction and sexuality are usually exposed to pollinator-mediated selection. Such selective pressures may be even stronger in heterantherous and pollen flowers, in which pollen contributes to both bee feeding and pollination, overcoming the “pollen dilemma” or the inability to perform both functions simultaneously. We describe the phenotypic gender and sexual organ morphology of flowers in two populations of Macairea radula (Melastomataceae), a heterantherous and buzz-pollinated species with pollen flowers. We estimated selection gradients on these traits through female and male fitness components. Both populations showed sizeable phenotypic gender variation, from strict hermaphrodites to increased femaleness or maleness. We found a continuous variation in style and stamen size, and this variation was correlated with corresponding shape values of both sexual organs. We detected bee-mediated selection towards short and long styles through seed number and towards intermediate degrees of heteranthery through pollen removal in one population, and selection towards increased maleness through pollen dispersal in both populations. Our results suggest that bee-mediated selection favors floral sex specialization and stylar dimorphism in M. radula, optimizing reproductive success and solving the pollen dilemma.

Linear Discrimination, Ordination, and the Visualization of Selection Gradients in Modern Morphometrics

2011 ◽  
Vol 38 (1) ◽  
pp. 100-114 ◽  
Author(s):  
Philipp Mitteroecker ◽  
Fred Bookstein
Keyword(s):  
Selection Gradients ◽  
Linear Discrimination

Measuring natural selection on multivariate phenotypic traits: a protocol for verifiable and reproducible analyses of natural selection

2019 ◽  
Vol 65 (3-4) ◽  
pp. 130-136 ◽  
Author(s):  
Facundo Xavier Palacio ◽  
Mariano Ordano ◽  
Santiago Benitez-Vieyra
Keyword(s):  
Regression Analysis ◽  
Natural Selection ◽  
Evolutionary Biology ◽  
Specific Model ◽  
Quadratic Model ◽  
Standard Errors ◽  
Phenotypic Traits ◽  
Linear Gradient ◽  
Selection Gradients ◽  
Model Residuals

The use of multiple regression analysis to quantify the regime and strength of natural selection in nature has been an influential approach in evolutionary biology over the last 36 years. However, many studies fail to report the protocol of estimation of selection coefficients (selection gradients) and the specific model assumptions, thus failing to verify and reproduce the estimation of selection coefficients. We present a brief overview of the Lande and Arnold’s approach and a step-by-step R routine to aid researchers to perform a verifiable and reproducible regression analysis of natural selection. The steps involved in the analysis include: (1) assessing collinearity between phenotypic traits, (2) testing normality of model residuals, and (3) testing multivariate normality of phenotypic traits. We also performed a series of simulations to test the effect of non-symmetrical (skewed) phenotypic traits on the estimation of linear selection gradients. These showed that the bias in the linear gradient increased with increased skewness in phenotypic traits for the quadratic model, whereas the linear gradient of a model with only linear terms was nearly independent of trait skewness. If none of the above assumptions are met, selection gradients need to be estimated from two separate equations, whereas standard errors must be computed using other methods (e.g. bootstrapping). We expect that the procedure outlined here and the availability of analytical codes motivate the verifiability and reproducibility of the Lande and Arnold’s approach in the study of microevolution.

scholarly journals Coevolution of cognitive abilities and identity signals in individual recognition systems

2020 ◽  
Vol 375 (1802) ◽  
pp. 20190467 ◽  
Author(s):  
Sara E. Miller ◽  
Michael J. Sheehan ◽  
H. Kern Reeve
Keyword(s):  
Cognitive Abilities ◽  
Phenotypic Diversity ◽  
Individual Recognition ◽  
Experimental Tests ◽  
Selection Gradients ◽  
Sensory Modalities ◽  
Signal Production ◽  
Recognition Systems ◽  
Multiple Species ◽  
Evolving Models

Social interactions are mediated by recognition systems, meaning that the cognitive abilities or phenotypic diversity that facilitate recognition may be common targets of social selection. Recognition occurs when a receiver compares the phenotypes produced by a sender with a template. Coevolution between sender and receiver traits has been empirically reported in multiple species and sensory modalities, though the dynamics and relative exaggeration of traits from senders versus receivers have received little attention. Here, we present a coevolutionary dynamic model that examines the conditions under which senders and receivers should invest effort in facilitating individual recognition. The model predicts coevolution of sender and receiver traits, with the equilibrium investment dependent on the relative costs of signal production versus cognition. In order for recognition to evolve, initial sender and receiver trait values must be above a threshold, suggesting that recognition requires some degree of pre-existing diversity and cognitive abilities. The analysis of selection gradients demonstrates that the strength of selection on sender signals and receiver cognition is strongest when the trait values are furthest from the optima. The model provides new insights into the expected strength and dynamics of selection during the origin and elaboration of individual recognition, an important feature of social cognition in many taxa. This article is part of the theme issue ‘Signal detection theory in recognition systems: from evolving models to experimental tests’.

scholarly journals Inference of selection gradients using performance measures as fitness proxies

2017 ◽  
Vol 8 (6) ◽  
pp. 663-677 ◽  
Author(s):  
Oliver D. Franklin ◽  
Michael B. Morrissey
Keyword(s):  
Performance Measures ◽  
Selection Gradients
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