scholarly journals ‘Junk’ DNA and long–term phenotypic evolution in Silene section Elisanthe (Caryophyllaceae)

2004 ◽  
Vol 271 (suppl_6) ◽  
Author(s):  
Thomas R. Meagher ◽  
Denise E. Costich
Keyword(s):  
Phenotypic Evolution ◽  
Junk Dna

scholarly journals The signature of competition in ecomorphological traits across the avian radiation

2020 ◽  
Vol 287 (1938) ◽  
pp. 20201585
Author(s):  
A. M. Chira ◽  
C. R. Cooney ◽  
J. A. Bright ◽  
E. J. R. Capp ◽  
E. C. Hughes ◽  
...  
Keyword(s):  
Species Interactions ◽  
Biological Diversity ◽  
Phenotypic Evolution ◽  
Shared Resources ◽  
Deep Time ◽  
Extant Species ◽  
Phenotypic Diversification ◽  
Best Fit

Competition for shared resources represents a fundamental driver of biological diversity. However, the tempo and mode of phenotypic evolution in deep-time has been predominantly investigated using trait evolutionary models which assume that lineages evolve independently from each other. Consequently, the role of species interactions in driving macroevolutionary dynamics remains poorly understood. Here, we quantify the prevalence for signatures of competition between related species in the evolution of ecomorphological traits across the bird radiation. We find that mechanistic trait models accounting for the effect of species interactions on phenotypic divergence provide the best fit for the data on at least one trait axis in 27 out of 59 clades ranging between 21 and 195 species. Where it occurs, the signature of competition generally coincides with positive species diversity-dependence, driven by the accumulation of lineages with similar ecologies, and we find scarce evidence for trait-dependent or negative diversity-dependent phenotypic evolution. Overall, our results suggest that the footprint of interspecific competition is often eroded in long-term patterns of phenotypic diversification, and that other selection pressures may predominantly shape ecomorphological diversity among extant species at macroevolutionary scales.

scholarly journals Fly wing evolution explained by a neutral model with mutational pleiotropy

2020 ◽  
Author(s):  
Daohan Jiang ◽  
Jianzhi Zhang
Keyword(s):  
Linear Correlation ◽  
Evolutionary Biology ◽  
Stabilizing Selection ◽  
Evolutionary Divergence ◽  
Phenotypic Evolution ◽  
Central Question ◽  
Evolutionary Patterns ◽  
Strong Linear Correlation ◽  
Mutational Variance

ABSTRACTTo what extent the speed of mutational production of phenotypic variation determines the rate of long-term phenotypic evolution is a central question in evolutionary biology. In a recent study, Houle et al. addressed this question by studying the mutational variation, microevolution, and macroevolution of locations of vein intersections on fly wings, reporting very slow phenotypic evolution relative to the rates of mutational input, high phylogenetic signals of these traits, and a strong, linear correlation between the mutational variance of a trait and its rate of evolution. Houle et al. examined multiple models of phenotypic evolution but found none consistent with all these observations. Here we demonstrate that the purported linear correlation between mutational variance and evolutionary divergence is an artifact. More importantly, patterns of fly wing evolution are explainable by a simple model in which the wing traits are neutral or neutral within a range of phenotypic values but their evolutionary rates are reduced because most mutations affecting these traits are purged owing to their pleiotropic effects on other traits that are under stabilizing selection. We conclude that the evolutionary patterns of fly wing morphologies are explainable under the existing theoretical framework of phenotypic evolution.

Long-term phenotypic evolution of bacteria

Nature ◽  
2014 ◽  
Vol 517 (7534) ◽  
pp. 369-372 ◽  
Author(s):  
Germán Plata ◽  
Christopher S. Henry ◽  
Dennis Vitkup
Keyword(s):  
Phenotypic Evolution

scholarly journals Trait–fitness associations do not predict within-species phenotypic evolution over 2 million years

2021 ◽  
Vol 288 (1943) ◽  
pp. 20202047
Author(s):  
Emanuela Di Martino ◽  
Lee Hsiang Liow
Keyword(s):  
Phenotypic Selection ◽  
Phenotypic Change ◽  
Ecological Interactions ◽  
Phenotypic Evolution ◽  
Time Intervals ◽  
Brood Chamber ◽  
Negative Trait ◽  
Simple Scaling ◽  
Multivariate Signals

Long-term patterns of phenotypic change are the cumulative results of tens of thousands to millions of years of evolution. Yet, empirical and theoretical studies of phenotypic selection are largely based on contemporary populations. The challenges in studying phenotypic evolution, in particular trait–fitness associations in the deep past, are barriers to linking micro- and macroevolution. Here, we capitalize on the unique opportunity offered by a marine colonial organism commonly preserved in the fossil record to investigate trait–fitness associations over 2 Myr. We use the density of female polymorphs in colonies of Antartothoa tongima as a proxy for fecundity, a fitness component, and investigate multivariate signals of trait–fitness associations in six time intervals on the backdrop of Pleistocene climatic shifts. We detect negative trait–fitness associations for feeding polymorph (autozooid) sizes, positive associations for autozooid shape but no particular relationship between fecundity and brood chamber size. In addition, we demonstrate that long-term trait patterns are explained by palaeoclimate (as approximated by ∂ 18 O), and to a lesser extent by ecological interactions (i.e. overgrowth competition and substrate crowding). Our analyses show that macroevolutionary outcomes of trait evolution are not a simple scaling-up from the trait–fitness associations.

scholarly journals The rate of polygenic mutation

1988 ◽  
Vol 51 (2) ◽  
pp. 137-148 ◽  
Author(s):  
Michael Lynch
Keyword(s):  
Genetic Variance ◽  
Phenotypic Evolution ◽  
Neutral Model ◽  
Base Population ◽  
Crop Species ◽  
Environmental Variance ◽  
Quantitative Estimates ◽  
Practical Implications ◽  
Term Response

SummaryBy application of the neutral model of phenotypic evolution, quantitative estimates of the rate of input of genetic variance by polygenic mutation can be extracted from divergence experiments as well as from the response of an inbred base population to selection. The analytical methods are illustrated through a survey of data on a diversity of organisms including Drosophila, Tribolium, mice, and several crop species. The mutational rate of introduction of genetic variance (Vm) scaled by the environmental variance (VE) is shown to vary between populations, species, and characters with a range of approximately 10−4 to 5 × 10−2. Vm/VE for Drosophila viability is somewhat below this range, while hybrid dysgenesis may temporarily inflate Vm/VE beyond 10−1. Potential sources of bias and error in the estimation of Vm are discussed, as are the practical implications of the observed limits to Vm/VE for projecting the long-term response to selection and for testing adaptational hypotheses.

scholarly journals Cause and consequences of genome duplication in haploid yeast populations

2018 ◽  
Author(s):  
Kaitlin J. Fisher ◽  
Sean W. Buskirk ◽  
Ryan C. Vignogna ◽  
Daniel A. Marad ◽  
Gregory I. Lang
Keyword(s):  
Genome Duplication ◽  
Neutral Evolution ◽  
Phenotypic Evolution ◽  
Deleterious Mutations ◽  
Structural Variants ◽  
Laboratory Evolution ◽  
Fitness Advantage ◽  
Whole Genome Duplications ◽  
Genome Duplications

ABSTRACTWhole genome duplications (WGD) represent important evolutionary events that shape future adaptation. WGDs are known to have occurred in the lineages leading to plants, fungi, and vertebrates. Changes to ploidy level impact the rate and spectrum of beneficial mutations and thus the rate of adaptation. Laboratory evolution experiments initiated with haploid Saccharomyces cerevisiae cultures repeatedly experience WGD. We report recurrent genome duplication in 46 haploid yeast populations evolved for 4,000 generations. We find that WGD confers a fitness advantage, and this immediate fitness gain is accompanied by a shift in genomic and phenotypic evolution. The presence of ploidy-enriched targets of selection and structural variants reveals that autodiploids utilize adaptive paths inaccessible to haploids. We find that autodiploids accumulate recessive deleterious mutations, indicating an increased capacity for neutral evolution. Finally, we report that WGD results in a reduced adaptation rate, indicating a trade-off between immediate fitness gains and long term adaptability.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

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