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Rxivist combines preprints from bioRxiv with data from Twitter to help you find the papers being discussed in your field. Currently indexing 62,747 bioRxiv papers from 278,434 authors.

Most downloaded bioRxiv papers, all time

in category evolutionary biology

4,155 results found. For more information, click each entry to expand.

4041: Effect of synaptic cell-to-cell transmission and recombination on the evolution of double mutants in HIV
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Posted to bioRxiv 24 Aug 2019

Effect of synaptic cell-to-cell transmission and recombination on the evolution of double mutants in HIV
81 downloads evolutionary biology

Jesse Kreger, Natalia L. Komarova, Dominik Wodarz

Recombination in HIV infection can impact virus evolution in vivo in complex ways, as has been shown both experimentally and mathematically. The effect of free virus versus synaptic, cell-to-cell transmission on the evolution of double mutants, however, has not been investigated. Here we do so by using a stochastic agent-based model. Consistent with data, we assume spatial constraints for synaptic but not for free-virus transmission. Two important effects of the viral spread mode are observed: (i) For disadvantageous mutants, synaptic transmission protects against detrimental effects of recombination on double mutant persistence. Under free virus transmission, recombination increases double mutant levels for negative epistasis, but reduces them for positive epistasis. This reduction for positive epistasis is much diminished under predominantly synaptic transmission, and recombination can in fact lead to increased mutant levels. (ii) The mode of virus spread also directly influences the evolutionary fate of double mutants. For disadvantageous mutants, double mutant production is the predominant driving force, and hence synaptic transmission leads to highest double mutant levels due to increased transmission efficiency. For advantageous mutants, double mutant spread is the most important force, and hence free virus transmission leads to fastest invasion due to better mixing. For neutral mutants, both production and spread of double mutants are important, and hence an optimal mixture of free virus and synaptic transmission maximizes double mutant fractions. Therefore, both free virus and synaptic transmission can enhance or delay double mutant evolution. Implications for drug resistance in HIV are discussed.

4042: Genetic and environmental canalization are not associated among altitudinally varying populations of Drosophila melanogaster
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Posted to bioRxiv 26 Jul 2019

Genetic and environmental canalization are not associated among altitudinally varying populations of Drosophila melanogaster
81 downloads evolutionary biology

Maria Pesevski, Ian Dworkin

Organisms are exposed to environmental and mutational effects influencing both mean and variance of phenotypes. These potentially deleterious effects can be ameliorated by the evolution of buffering (canalizing) mechanisms, resulting in reduced phenotypic variation. Under some population genetics models, the circumstances under which genetic canalization evolves is limited. As such, it has been argued that canalizing mechanisms for environmental and mutational stresses may co-evolve, and will be correlated. Yet, empirical evidence has not consistently supported this prediction. In a recent study, a population of Drosophila melanogaster adapted to high altitude showed evidence of genetic decanalization relative to low-altitude populations. Using these populations, we tested if these populations also varied for environmental canalization. We reared strains derived from these populations under different temperature rearing environments. Using the Drosophila wing, we quantified size, shape, cell density and frequencies of mutational defects. We observed the expected differences in size, shape, cell density and mutational defects between the high- and low-altitude populations. However, we observed little evidence for a relationship between a number of measures of environmental canalization with population of origin or visible defect frequency. Our results do not support the predicted association between genetic and environmental canalization.

4043: Phylogenetic Tree-based Pipeline for Uncovering Mutational Patterns during Influenza Virus Evolution
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Posted to bioRxiv 19 Jul 2019

Phylogenetic Tree-based Pipeline for Uncovering Mutational Patterns during Influenza Virus Evolution
81 downloads evolutionary biology

Fransiskus Xaverius Ivan, Akhila Deshpande, Chun Wei Lim, Xinrui Zhou, Jie Zheng, Chee-Keong Kwoh

Various computational and statistical approaches have been proposed to uncover the mutational patterns of rapidly evolving influenza viral genes. Nonetheless, the approaches mainly rely on sequence alignments which could potentially lead to spurious mutations obtained by comparing sequences from different clades that coexist during particular periods of time. To address this issue, we propose a phylogenetic tree-based pipeline that takes into account the evolutionary structure in the sequence data. Assuming that the sequences evolve progressively under a strict molecular clock, considering a competitive model that is based on a certain Markov model, and using a resampling approach to obtain robust estimates, we could capture statistically significant single-mutations and co-mutations during the sequence evolution. Moreover, by considering the results obtained from analyses that consider all paths and the longest path in the resampled trees, we can categorize the mutational sites and suggest their relevance. Here we applied the pipeline to investigate the 50 years of evolution of the HA sequences of influenza A/H3N2 viruses. In addition to confirming previous knowledge on the A/H3N2 HA evolution, we also demonstrate the use of the pipeline to classify mutational sites according to whether they are able to enhance antigenic drift, compensate other mutations that enhance antigenic drift, or both.

4044: Large single-locus effects for maturation timing are mediated via condition variation in Atlantic salmon
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Posted to bioRxiv 24 Sep 2019

Large single-locus effects for maturation timing are mediated via condition variation in Atlantic salmon
81 downloads evolutionary biology

Paul Vincent Debes, Nikolai Piavchenko, Annukka Ruokolainen, Outi Ovaskainen, Jacqueline E Moustakas-Verho, Noora Parre, Tutku Aykanat, Jaakko Erkinaro, Craig R Primmer

Sexual maturation is a pivotal life-history trait that balances the probabilities between mortality and reproduction. Environmental vs. genetic contributions to maturation component traits, such as somatic growth and body condition, remain uncertain because of difficulties in determining causality. In Atlantic salmon, maturation timing associates with a large-effect locus around vgll3, which also links with growth, condition, and maturation in mammals. We investigate environmental vs. genetic contributions to maturation and its component traits by combining controlled breeding with common-garden experimentation in two temperatures. We test whether vgll3 associates with first-year maturation of male salmon and, to avoid reverse causality, whether vgll3 effects express via growth or condition in the males' non-maturing female relatives. Across 41 families, 4% of males matured in the cold vs. 39% in the warm environment. Maturation rate differed 3.3- to 4.6-fold between vgll3 genotypes, which also explained around 30% of maturation heritability. Female condition differed up to 2% between vgll3 genotypes, which also explained 6-17% of condition heritability. Non-significant vgll3 effects on female length were antagonistic to those for condition but of equal proportional size. When accounting for vgll3 effects, positive genetic correlations between male maturation and female growth increased, whereas those between male maturation and condition decreased, supporting an antagonistic effect of vgll3 on growth and condition. The results indicate that large vgll3 effects on maturation are mediated via large condition effects and suggest vgll3 as a candidate locus for controlling the resource allocation trade-off between somatic growth and body condition.

4045: Novitski's distal shift in paracentric inversion evolution
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Posted to bioRxiv 03 Dec 2018

Novitski's distal shift in paracentric inversion evolution
81 downloads evolutionary biology

Spencer A Koury

In Drosophila pseudoobscura younger chromosomal inversions tend to be found distal to older inversions. By examining phylogenetic series of overlapping inversions for 134 gene arrangements of 13 chromosomes this pattern was extended to five additional Drosophila species. This distinct pattern arose repeatedly and independently in all six species and likely reflects an underlying principle of chromosome evolution. In this study it is illustrated how transmission of distal inversions is always favored in female meiosis when crossing over in homosequential regions of overlapping inversions generates asymmetric dyads. This cytogenetic mechanism for female meiotic drive is described in detail and advanced as an explanation for the distal shift in phylogenetic series of overlapping inversions as well as several better known patterns in the evolution of serially inverted chromosomes.

4046: Ability of the misfolding avoidance hypothesis to explain protein evolutionary rates in the light of empirical evidence
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Posted to bioRxiv 10 Sep 2019

Ability of the misfolding avoidance hypothesis to explain protein evolutionary rates in the light of empirical evidence
81 downloads evolutionary biology

German Plata, Dinara R. Usmanova, Dennis Vitkup

In this brief communication we further discuss the relationship between the rate of protein evolution and the misfolding avoidance hypothesis (MAH), as it was originally proposed. We also discuss results of empirical tests of the MAH, and demonstrate the lack of any substantial correlation between protein stability, quantified by protein folding free energy, and protein evolutionary rates. Based on multiple available evidence, the MAH is unlikely to play any major role in explaining a strong negative correlation between protein abundance and the protein molecular clock.

4047: Parallel genomic architecture underlies repeated sexual signal divergence in Hawaiian Laupala crickets
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Posted to bioRxiv 14 Aug 2019

Parallel genomic architecture underlies repeated sexual signal divergence in Hawaiian Laupala crickets
81 downloads evolutionary biology

Thomas Blankers, Kevin P. Oh, Kerry L. Shaw

When the same phenotype evolves repeatedly, we can explore the predictability of genetic changes underlying phenotypic evolution. Theory suggests that genetic parallelism is less likely when phenotypic changes are governed by many small-effect loci compared to few of major effect, because different combinations of genetic changes can result in the same quantitative outcome. However, some genetic trajectories might be favored over others, making a shared genetic basis to repeated polygenic evolution more likely. To examine this, we studied the genetics of parallel male mating song evolution in the Hawaiian cricket Laupala . We compared quantitative trait loci (QTL) underlying song divergence in three species pairs varying in phenotypic distance. We tested whether replicated song divergence between species involves the same QTL and the likelihood that sharing QTL is related to phenotypic effect sizes. Contrary to theoretical predictions, we find substantial parallelism in polygenic genetic architectures underlying repeated song divergence. QTL overlapped more than expected based on simulated QTL analyses. Interestingly, QTL effect size did not predict QTL sharing, but did correlate with magnitude of phenotypic divergence. We highlight potential mechanisms driving these constraints on cricket song evolution and discuss a scenario that consolidates empirical quantitative genetic observations with micro-mutational theory.

4048: Consistency and identifiability of the polymorphism-aware phylogenetic models
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Posted to bioRxiv 30 Jul 2019

Consistency and identifiability of the polymorphism-aware phylogenetic models
80 downloads evolutionary biology

Rui Borges, Carolin Kosiol

Polymorphism-aware phylogenetic models (PoMo) constitute an alternative approach for species tree estimation from genome-wide data. PoMo builds on the standard substitution models of DNA evolution but expands the classic alphabet of the four nucleotide bases to include polymorphic states. By doing so, PoMo accounts for ancestral and current intra-population variation, while also accommodating population-level processes ruling the substitution process (e.g. genetic drift, mutations, allelic selection). PoMo has shown to be a valuable tool in several phylogenetic applications but a proof of statistical consistency (and identifiability, a necessary condition for consistency) is lacking. Here, we prove that PoMo is identifiable and, using this result, we further show that the maximum a posteriori (MAP) tree estimator of PoMo is a consistent estimator of the species tree. We complement our theoretical results with a simulated data set mimicking the diversity observed in natural populations exhibiting incomplete lineage sorting. We implemented PoMo in a Bayesian framework and show that the MAP tree easily recovers the true tree for typical numbers of sites that are sampled in genome-wide analyses.

4049: Induction of hierarchy and time through one-dimensional probability space with certain topologies
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Posted to bioRxiv 24 Sep 2019

Induction of hierarchy and time through one-dimensional probability space with certain topologies
80 downloads evolutionary biology

Shun Adachi

In a previous study, the authors utilized a single dimensional operationalization of species density that at least partially demonstrated dynamic system behavior. For completeness, a theory needs to be developed related to homology/cohomology, induction of the time dimension, and system hierarchies. The topological nature of the system is carefully examined and for testing purposes, species density data for a wild Dictyostelia community data are used in conjunction with data derived from liquid-chromatography mass spectrometry of proteins. Utilizing a Clifford algebra, a congruent zeta function, and a Weierstraß ℘ function in conjunction with a type VI Painlevé equation, we confirmed the induction of hierarchy and time through one-dimensional probability space with certain topologies. This process also served to provide information concerning interactions in the model. The previously developed “small s ” metric can characterize dynamical system hierarchy and interactions, using only abundance data along time development.

4050: Phylogenomics investigation of sparids (Teleostei: Spariformes) using high-quality proteomes highlights the importance of taxon sampling
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Posted to bioRxiv 24 Aug 2019

Phylogenomics investigation of sparids (Teleostei: Spariformes) using high-quality proteomes highlights the importance of taxon sampling
80 downloads evolutionary biology

Paschalis Natsidis, Alexandros Tsakogiannis, P. Pavlidis, Costas S Tsigenopoulos, T Manousaki

Sparidae (Teleostei: Spariformes) are a family of fish constituted by approximately 150 species with high popularity and commercial value, such as porgies and seabreams. Although the phylogeny of this family has been investigated multiple times, its position among other teleost groups remains ambiguous. Most studies have used a single or few genes to decipher the phylogenetic relationships of sparids. Here, we conducted a phylogenomic attempt to resolve the position of the family using five recently available Sparidae gene-sets and 26 available fish proteomes from species with a sequenced genome, to ensure higher quality of the predicted genes. A thorough phylogenomic analysis suggested that Tetraodontiformes (puffer fish, sunfish) are the closest relatives to sparids than all other groups used, a finding that contradicts our previous phylogenomic analysis that proposed the yellow croaker and the european seabass as closest taxa of sparids. By analytically comparing the methodologies applied in both cases, we show that this discordance is not due to different orthology assignment algorithms; on the contrary, we prove that it is caused by the increased taxon sampling of the present study, outlining the great importance of this aspect in phylogenomic analyses in general.

4051: A multivariate phylogenetic comparative method incorporating a flexible function between discrete and continuous traits
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Posted to bioRxiv 20 Sep 2019

A multivariate phylogenetic comparative method incorporating a flexible function between discrete and continuous traits
79 downloads evolutionary biology

Yuki Haba, Nobuyuki Kutsukake

One major challenge of using the phylogenetic comparative method (PCM) is the analysis of the evolution of interrelated continuous and discrete traits in a single multivariate statistical framework. In addition, more intricate parameters such as branch-specific directional selection have rarely been integrated into such multivariate PCM frameworks. Here, originally motivated to analyze the complex evolutionary trajectories of group size (continuous variable) and social systems (discrete variable) in African subterranean rodents, we develop a flexible approach using approximate Bayesian computation (ABC). Specifically, our multivariate ABC-PCM method allows the user to flexibly model an underlying latent evolutionary function between continuous and discrete traits. The ABC-PCM also simultaneously incorporates complex evolutionary parameters such as branch-specific selection. This study highlights the flexibility of ABC-PCMs in analyzing the evolution of phenotypic traits interrelated in a complex manner.

4052: The NAD+-dependent deacetylase Sir2 enables evolution of new traits by regulating distinct gene sets in two yeast species, Saccharomyces cerevisiae and Kluyveromyces lactis
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Posted to bioRxiv 13 Aug 2019

The NAD+-dependent deacetylase Sir2 enables evolution of new traits by regulating distinct gene sets in two yeast species, Saccharomyces cerevisiae and Kluyveromyces lactis
79 downloads evolutionary biology

Kristen M Humphrey, Lisha Zhu, Meleah A Hickman, Shirin Hasan, Haniam Maria, Tao Liu, Laura N Rusche

Evolutionary adaptation increases the fitness of an organism in its environment. It can occur through rewiring of gene regulatory networks, such that an organism responds appropriately to environmental changes. We investigated whether sirtuin deacetylases, which repress transcription and require NAD+ for activity, could facilitate the evolution of potentially adaptive responses by serving as transcriptional rewiring points. If so, bringing genes under the control of sirtuins could enable organisms to mount appropriate responses to stresses that decrease NAD+ levels. To explore how the genomic targets of sirtuins shift over evolutionary time, we compared two yeast species, Saccharomyces cerevisiae and Kluyveromyces lactis that display differences in cellular metabolism and lifecycle timing in response to nutrient availability. We identified sirtuin-regulated genes through a combination of chromatin immunoprecipitation and RNA expression. In both species, regulated genes were associated with NAD+ homeostasis, mating, and sporulation, but the specific genes differed. In addition, regulated genes in K. lactis were associated with other processes, including utilization of non-glucose carbon sources, heavy metal efflux, DNA synthesis, and production of the siderophore pulcherrimin. Consistent with the species-restricted regulation of these genes, sirtuin deletion impacted relevant phenotypes in K. lactis but not S. cerevisiae. Finally, sirtuin-regulated gene sets were depleted for broadly-conserved genes, consistent with sirtuins regulating processes restricted to a few species. Taken together, these results are consistent with the notion that sirtuins serve as rewiring points that allow species to evolve distinct responses to low NAD+ stress.

4053: The structural proteome for the primordial glycolysis/gluconeogenesis
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Posted to bioRxiv 18 Jul 2019

The structural proteome for the primordial glycolysis/gluconeogenesis
79 downloads evolutionary biology

Isabela J. B. do O, Thais G. Rego, Marco Jose, Savio T de Farias

Comprehending the constitution of early biological metabolism is indispensable for the understanding of the origin and evolution of life on Earth. Here, we analyzed the structural proteome before the Last Universal Common Ancestor (LUCA) based in the reconstruction of the ancestral sequences and structure for proteins involved in glycolysis/gluconeogenesis. The results are compatible with the notion that the first portions of the proteins were the areas homologous to the present-day catalytic sites. Those proto-proteins had a simple function: binding to cofactors. Upon the accretion of new elements to the structure, the catalytic function could have emerged. Also, the first structural motifs might have been related to the emergence of the different proteins that work in modern organisms.

4054: Utility of the Onchocerca volvulus mitochondrial genome for delineation of parasite transmission zones
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Posted to bioRxiv 12 Aug 2019

Utility of the Onchocerca volvulus mitochondrial genome for delineation of parasite transmission zones
79 downloads evolutionary biology

Katie E Crawford, Shannon M Hedtke, Stephen R Doyle, Annette C. Kuesel, Samuel Armoo, Mike Osei-Atweneboana, Warwick N. Grant

In 2012, the reduction in Onchocerca volvulus infection prevalence through long-term mass ivermectin distribution in African meso- and hyperendemic areas motivated expanding control of onchocerciasis (river blindness) as a public health problem to elimination of parasite transmission. Given the large contiguous hypo-, meso- and hyperendemic areas with an estimated population of 204 million, sustainable elimination requires an understanding of the geographic, and in turn genetic, boundaries of different parasite populations to ensure interventions are only stopped where the risk of re-introduction of the parasite through vector or human migration from areas with ongoing transmission is acceptable. These boundaries, which define the transmission zones of the parasite, may be delineated by characterising the parasite genetic population structure within and between potential zones. We analysed whole mitochondrial genome sequences of 189 O. volvulus adults to determine the pattern of genetic similarity across three West African countries: Ghana, Mali, and Cote d'Ivoire. Population structure measures indicate that parasites from the Pru, Daka and Black Volta/Tombe river basins in central Ghana belong to one parasite population, showing that different river basins cannot be assumed to constitute independent transmission zones. This research forms the basis for developing tools for elimination programs to delineate transmission zones, to estimate the risk of parasite re-introduction via vector or human movement when mass ivermectin administration is stopped in one area while transmission is ongoing in others, to identify the origin of infections detected post-treatment cessation, and to investigate whether migration contributes to persisting prevalence levels during interventions.

4055: Genes for ash tree resistance to an insect pest identified via comparative genomics
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Posted to bioRxiv 18 Sep 2019

Genes for ash tree resistance to an insect pest identified via comparative genomics
79 downloads evolutionary biology

Laura J. Kelly, William J Plumb, David W Carey, Mary E Mason, Endymion D Cooper, William Crowther, Alan T. Whittemore, Stephen J Rossiter, Jennifer L Koch, Richard J A Buggs

Genome-wide discovery of candidate genes for functional traits within a species typically involves the sequencing of large samples of phenotyped individuals, or linkage analysis through multiple generations. When a trait occurs repeatedly among phylogenetically independent lineages within a genus, a more efficient approach may be to identify genes via detection of amino acid residues shared by species possessing that trait. Here, by taking this approach, we identify candidate loci in the genus Fraxinus (ash trees) for resistance to the emerald ash borer beetle (EAB; Agrilus planipennis), a pest species that appears innocuous to otherwise healthy ash in its native East Asian range but is highly destructive in North America and poses a threat to ash trees in Europe. Assembling whole genome sequences for 24 diploid species and subspecies of ash, and estimating resistance to EAB for 26 taxa from egg bioassays, we find 53 genes containing amino acid variants shared between two or more independent Fraxinus lineages with EAB-resistant species, that are unlikely to be due to chance or undetected paralogy. Of these, seven genes have putative roles relating to the phenylpropanoid biosynthesis pathway and 17 are potentially connected to herbivore recognition, defence signalling or programmed cell death. We also find that possible loss-of-function mutations among our 53 candidate genes are more frequent in susceptible species, than in resistant ones. Patterns of polymorphism for the EAB-associated amino acid variants in ash trees representing different European populations suggest that selection may be able to enhance their resistance to EAB.

4056: Genome-wide misexpression associated with hybrid sterility in Mimulus (monkeyflower)
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Posted to bioRxiv 30 Aug 2019

Genome-wide misexpression associated with hybrid sterility in Mimulus (monkeyflower)
78 downloads evolutionary biology

Rachel E. Kerwin, Andrea L Sweigart

Divergence in gene expression regulation is common between closely related species and may give rise to incompatibilities in their hybrid progeny. In this study, we investigated the relationship between regulatory evolution within species and reproductive isolation between species. We focused on a well-studied case of hybrid sterility between Mimulus guttatus and M. nasutus, two closely related yellow monkeyflower species, that is caused by two epistatic loci, hybrid male sterility 1 (hms1) and hybrid male sterility 2 (hms2). We quantified and compared global transcript abundance across male and female reproductive tissues (i.e. stamens and carpels) of M. guttatus and M. nasutus, as well as sterile and fertile progeny from an advanced M. nasutus-M. guttatus introgression line that carries the hms1-hms2 incompatibility. We observed substantial variation in transcript abundance between M. guttatus and M. nasutus, including distinct but overlapping patterns of tissue-biased expression, providing evidence for regulatory divergence between these species. Furthermore, we found pervasive genome-wide misexpression exclusively associated with hybrid sterility - only observed in the affected tissues (i.e. stamens) of sterile introgression hybrids. Examining patterns of allele-specific expression in sterile and fertile hybrids, we found evidence of cis- and trans-regulatory divergence, as well as cis-trans compensatory evolution (likely to be driven by stabilizing selection). However, regulatory divergence does not appear to cause misexpression in sterile hybrids, which instead likely manifests as a downstream consequence of sterility itself.

4057: Evolutionary changes of phosphoenolpyruvate transporter (PPT) during the emergence of C4 photosynthesis
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Posted to bioRxiv 24 Jul 2019

Evolutionary changes of phosphoenolpyruvate transporter (PPT) during the emergence of C4 photosynthesis
78 downloads evolutionary biology

Ming-Ju Amy Lyu, Yaling Wang, Jianjun Jiang, Genyun Chen, Xin-Guang Zhu

C4 photosynthesis is a complex trait, which evolved from its ancestral C3 photosynthesis by recruiting pre-existing genes. The evolutionary history of enzymes involved in the C4 shuttle has been extensively studied. Here we analyze the evolutionary changes of a phosphoenolpyruvate (PEP) transporter (PPT) during its recruitment from C3 to C4 photosynthesis. Our analysis shows that 1) among the two PPT paralogs, i.e. PPT1 and PPT2, PPT1 is an ancestral copy while PPT2 is a derived copy; 2) PPT1 gained increased transcript abundance, gained more rapid and long-lasting responses to light during C3 to C4 evolution, while PPT2 lost its responsiveness to light; 3) during C4 evolution, PPT1 shifted its expression from predominantly in root to in leaf, and from bundle sheath cell to mesophyll cell, supporting that PPT1 was recruited into C4 photosynthesis; 4) PPT1 gained a number of new cis-elements during C4 evolution; 5) C4 PPT1 can complement the phenotype of Arabidopsis PPT1 loss-of-function mutant, suggesting that it is a bidirectional transporter and its transport direction did not alter during C4 evolution. We finally discuss mechanistic linkages between these observed changes in PPT1 and C4 photosynthesis evolution.

4058: Enhanced leaky sex expression is an adaptive plastic response to pollen limitation in the dioecious plant Mercurialis annua
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Posted to bioRxiv 15 Jul 2019

Enhanced leaky sex expression is an adaptive plastic response to pollen limitation in the dioecious plant Mercurialis annua
78 downloads evolutionary biology

Guillaume Cossard, John R. Pannell

Phenotypic plasticity is all but ubiquitous across the tree of life, but clear demonstrations that it is adaptive are rare. In dioecious plants, males and females frequently show 'leaky' sex expression, with individuals occasionally producing flowers of the opposite sex. Here, we ask whether leaky sex expression in the wind-pollinated dioecious herb Mercurialis annua is plastically responsive to its mating context, and whether such plasticity is adaptive. We compared experimental populations of females growing either with or without males. Females growing in the absence of males were leakier in their sex expression than controls with males, producing more than twice as many male flowers, and they enjoy much greater fitness. We discuss differences in the degree of plasticity between ploidal races of annua Mercurialis in terms of likely differences in the reliability of the signal plants may perceive for the presence of males in their populations. Our results provide a striking instance of adaptive plasticity in the reproductive behavior of plants and draw attention to possible constraints on plasticity when the environmental signals individuals receive are unreliable.

4059: Genetic variation in parental effects contribute to the evolutionary potential of prey responses to predation risk
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Posted to bioRxiv 28 Aug 2019

Genetic variation in parental effects contribute to the evolutionary potential of prey responses to predation risk
78 downloads evolutionary biology

Natasha Tigreros, Anurag A. Agrawal, Jennifer S. Thaler

Despite the ubiquity of parental effects and their potential impact on evolutionary dynamics, their contribution to the evolution of ecologically relevant adaptations remains poorly understood. Using quantitative genetics, here we demonstrate that parental effects contribute substantially to the evolutionary potential of larval antipredator responses in a leaf beetle (Leptinotarsa decemlineata). Previous research showed that larger L. decemlineata larvae elicit stronger antipredator responses, and mothers perceiving predators improved offspring responses by increasing intraclutch cannibalism, an extreme form of offspring provisioning. We now report substantial additive genetic variation underlying maternal ability to induce intraclutch cannibalism, indicating the potential of this adaptive maternal effect to evolve by natural selection. We also show that paternal size, a heritable trait, impacted larval responses to predation risk, but that larval responses themselves had little additive genetic variation. Together, these results demonstrate how larval responses to predation risk can evolve via two types of parental effects, both of which provide indirect sources of genetic variation for offspring traits.

4060: Senescence and entrenchment in evolution of amino acid sites
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Posted to bioRxiv 07 Oct 2019

Senescence and entrenchment in evolution of amino acid sites
78 downloads evolutionary biology

Anastasia V. Stolyarova, Elena Nabieva, V. V. Ptushenko, Alexander Favorov, Anfisa V Popova, A. D. Neverov, Georgii A. Bazykin

Amino acid propensities at a site change in the course of protein evolution. This may happen for two reasons. Changes may be triggered by substitutions at epistatically interacting sites elsewhere in the genome; alternatively, they may arise due to environmental changes that are external to the genome. Here, we design a framework for distinguishing between these alternatives. Using analytical modelling and simulations, we show that they cause opposite dynamics of the fitness of the allele currently occupying the site: its fitness tends to increase with the time since its origin due to epistasis (“entrenchment”), but to decrease due to random environmental fluctuations (“senescence”). We analyse the phylogenetic distribution of substitutions in nuclear genomes, and show that among the amino acids originating at negatively selected sites of vertebrates, nearly all experience strong entrenchment. By contrast, among the amino acids originating at positively selected sites, 18% experience senescence. A similar pattern is observed in phylogenies of insects. We propose that senescence of the current allele is a cause of adaptive evolution.

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