114 Works

The effects of age on the demography of a perennial plant depend on interactions with size and environment

Heide Maria Baden, Johan Pedder Dahlgren, Deborah Ann Roach, Fritz Hans Schweingruber, Kasper Reitzel & Kim Lundgreen
1. Age-dependence of the demographic rates survival, fecundity and individual growth is a fundamental aspect of population biological theory. Knowledge about plant ageing can also be important for conservation and agriculture as it will improve the accuracy of population viability assessments and long-term performance assessments in perennial crops. Recent studies show age effects on demographic rates for several plant species, yet much remains to be learned about the patterns and mechanisms of plant ageing, particularly...

Unique genetic signatures of local adaptation over space and time for diapause, an ecologically relevant complex trait, in Drosophila melanogaster

Priscilla A Erickson, Cory A Weller, Daniel Y Song, Paul Schmidt, Alan O Bergland & Alyssa Bangerter
Organisms living in seasonally variable environments utilize cues such as light and temperature to induce plastic responses, enabling them to exploit favorable seasons and avoid unfavorable ones. Local adapation can result in variation in seasonal responses, but the genetic basis and evolutionary history of this variation remains elusive. Many insects, including Drosophila melanogaster, are able to undergo an arrest of reproductive development (diapause) in response to unfavorable conditions. In D. melanogaster, the ability to diapause...

Data from: A generation time effect on the rate of molecular evolution in bacteria

Cory Andrew Weller, Martin Wu & Cory Weller
Molecular evolutionary rate varies significantly among species and a strict global molecular clock has been rejected across the tree of life. Generation time is one primary life-history trait that influences the molecular evolutionary rate. Theory predicts that organisms with shorter generation times evolve faster because of the accumulation of more DNA replication errors per unit time. While the generation-time effect has been demonstrated consistently in plants and animals, the evidence of its existence in bacteria...

Data from: The extent and genetic basis of phenotypic divergence in life history traits in Mimulus guttatus

Jannice Friedman, Alex D. Twyford, John H. Willis & Benjamin K. Blackman
Differential natural selection acting on populations in contrasting environments often results in adaptive divergence in multivariate phenotypes. Multivariate trait divergence across populations could be caused by selection on pleiotropic alleles or through many independent loci with trait-specific effects. Here, we assess patterns of association between a suite of traits contributing to life history divergence in the common monkeyflower, Mimulus guttatus, and examine the genetic architecture underlying these correlations. A common garden survey of 74 populations...

Data from: Challenging the inbreeding hypothesis in a eusocial mammal: population genetics of the naked mole-rat, Heterocephalus glaber.

Colleen M. Ingram, Nicholas J. Troendle, Clare A. Gill, Stanton Braude & Rodney L. Honeycutt
The role of genetic relatedness in the evolution of eusociality has been the topic of much debate, especially when contrasting eusocial insects with vertebrates displaying reproductive altruism. The naked mole-rat, Heterocephalus glaber, was the first described eusocial mammal. Although this discovery was based on an ecological constraints model of eusocial evolution, early genetic studies reported high levels of relatedness in naked mole-rats, providing a compelling argument that low dispersal rates and consanguineous mating (inbreeding as...

Data from: Adaptive dynamics of cuticular hydrocarbons in Drosophila

Subhash Rajpurohit, Robert Hanus, Vladimir Vrkoslav, Emily L. Behrman, Alan O. Bergland, Dmitri Petrov, Josef Cvacka & Paul S. Schmidt
Cuticular hydrocarbons (CHCs) are hydrophobic compounds deposited on the arthropod cuticle that are of functional significance with respect to stress tolerance, social interactions, and mating dynamics. We characterized CHC profiles in natural populations of Drosophila melanogaster at five levels: across a latitudinal transect in the eastern U.S., as a function of developmental temperature during culture, across seasonal time in replicate years, and as a function of rapid evolution in experimental mesocosms in the field. Furthermore,...

Data from: Seasonal ecosystem metabolism across shallow benthic habitats measured by aquatic eddy covariance

Karl M. Attard, Ivan F. Rodil, Ronnie N. Glud, Peter Berg, Joanna Norkko & Alf Norkko
This submission consists of 40 eddy covariance datasets collected from six shallow sites in the Baltic Sea over an 18 month period. Hourly fluxes were extracted from the high-density data streams and were used to compute daily rates of benthic metabolism (gross primary production (GPP), respiration (R), and net ecosystem metabolism (NEM); in mmol O2 m-2 d-1). These were converted to C assuming an O2 : C of 1.0 for GPP and R. A description...

Data from: Two subunits of human ORC are dispensable for DNA replication and proliferation

Etsuko Shibata, Manjari Kiran, Yoshiyuki Shibata, Samarendra Singh, Shashi Kiran & Anindya Dutta
The six-subunit Origin Recognition Complex (ORC) is believed to be an essential eukaryotic ATPase that binds to origins of replication as a ring-shaped heterohexamer to load MCM2-7 and initiate DNA replication. We have discovered that human cell lines in culture proliferate with intact chromosomal origins of replication after disruption of both alleles of ORC2 or of the ATPase subunit, ORC1. The ORC1 or ORC2-depleted cells replicate with decreased chromatin loading of MCM2-7 and become critically...

Data from: Archaeogenomic evidence reveals prehistoric matrilineal dynasty

Douglas J. Kennett, Stephen Plog, Richard J. George, Brendan J. Culleton, Adam S. Watson, Pontus Skoglund, Nadin Rohland, Swapan Mallick, Kristin Stewardson, Logan Kistler, Steven A. LeBlanc, Peter M. Whiteley, David Reich & George H. Perry
For societies with writing systems, hereditary leadership is documented as one of the hallmarks of early political complexity and governance. In contrast, it is unknown whether hereditary succession played a role in the early formation of prehistoric complex societies that lacked writing. Here we use an archaeogenomic approach to identify an elite matriline that persisted between 800 and 1130 CE in Chaco Canyon, the centre of an expansive prehistoric complex society in the Southwestern United...

Data from: Is there a disease-free halo at species range limits? The co-distribution of anther-smut disease and its host species

Emily L. Bruns, Janis Antonovics & Michael Hood
1. While disease is widely recognized as affecting host population size, it has rarely been considered to play a role in determining host range limits. Many diseases may not be able to persist near the range limit if host population density falls below the critical threshold level for pathogen invasion. However, in vector- and sexually-transmitted diseases, pathogen transmission may be largely independent of host density and theory demonstrates that diseases with frequency-dependent transmission may persist...

Data from: Early changes in transient adenosine during cerebral ischemia and reperfusion injury

Mallikarjunarao Ganesana & B. Jill Venton
Adenosine is an important neuromodulator in the central nervous system, and tissue adenosine levels increase during ischemic events, attenuating excitotoxic neuronal injury. Recently, our lab developed an electrochemical fast-scan cyclic voltammetry (FSCV) method that identified rapid, spontaneous changes in adenosine concentrations that last only about 3 seconds. Here, we investigated the effects of cerebral ischemia and reperfusion on the concentration and frequency of transient adenosine release in the caudate-putamen. In anesthetized rats, data were collected...

Data from: A low-threshold potassium current enhances sparseness and reliability in a model of avian auditory cortex

Margot C. Bjoring & C. Daniel Meliza
Birdsong is a complex vocal communication signal, and like humans, birds need to discriminate between similar sequences of sound with different meanings. The caudal mesopallium (CM) is a cortical-level auditory area implicated in song discrimination. CM neurons respond sparsely to conspecific song and are tolerant of production variability. Intracellular recordings in CM have identified a diversity of intrinsic membrane dynamics, which could contribute to the emergence of these higher-order functional properties. We investigated this hypothesis...

Data from: The contribution of maternal effects to selection response: an empirical test of competing models

Joel William McGlothlin & Laura F. Galloway
Maternal effects can dramatically influence the evolutionary process, in some cases facilitating and in others hindering adaptive evolution. Maternal effects have been incorporated into quantitative genetic models using two theoretical frameworks: the variance-components approach, which partitions variance into direct and maternal components, and the trait-based approach, which assumes that maternal effects are mediated by specific maternal traits. Here, we demonstrate parallels between these models and test their ability to predict evolutionary change. First, we show...

Sex linkage of the skeletal muscle sodium channel gene (SCN4A) explains apparent deviations from Hardy–Weinberg equilibrium of tetrodotoxin-resistance alleles in garter snakes (Thamnophis sirtalis)

Kerry Gendreau, Michael Hague, Chris Feldman, , & Joel McGlothlin
The arms race between tetrodotoxin-bearing Pacific newts (Taricha) and their garter snake predators (Thamnophis) in western North America has become a classic example of coevolution, shedding light on predator-prey dynamics, the molecular basis of adaptation, and patterns of convergent evolution. Newts are defended by tetrodotoxin (TTX), a neurotoxin that binds to voltage-gated sodium channels (Nav proteins), arresting electrical activity in nerves and muscles and paralyzing would-be predators. However, populations of the common garter snake (T....

Data from: The role of infectious disease in the evolution of females: evidence from anther-smut disease on a gynodioecious alpine carnation

Emily L. Bruns, Ian Miller, Michael E. Hood, Valentina Carasso & Janis Antonovics
In flowering plants, the evolution of females is widely hypothesized to be the first step in the evolutionary pathway to separate male and female sexes, or dioecy. Natural enemies have the potential to drive this evolution if they preferentially attack hermaphrodites over females. We studied sex-based differences in exposure to anther-smut (Microbotryum), a sterilizing pollinator-transmitted disease, in Dianthus pavonius, a gynodioecious perennial herb. We found that within a heavily diseased population, females consistently had lower...

Data from: Biparental chloroplast inheritance leads to rescue from cytonuclear incompatibility

Karen B. Barnard-Kubow, Morgan A. McCoy & Laura F. Galloway
Although organelle inheritance is predominantly maternal across animals and plants, biparental chloroplast inheritance has arisen multiple times in the angiosperms. Biparental inheritance has the potential to impact the evolutionary dynamics of cytonuclear incompatibility, interactions between nuclear and organelle genomes that are proposed to be among the earliest types of genetic incompatibility to arise in speciation. We examine the interplay between biparental inheritance and cytonuclear incompatibility in Campanulastrum americanum, a plant species exhibiting both traits. We...

Sperm morphology and count vary with fine-scale changes in local density in a wild lizard population

Matthew C Kustra, Ariel F Kahrl, Aaron M Reedy, Daniel A Warner & Robert M Cox
Given that sperm production can be costly, theory predicts that males should optimally adjust the quantity and/or quality of their sperm in response to their social environment to maximize their paternity success. Although experiments demonstrate that males can alter their ejaculates in response to manipulations of the social environment and studies show that ejaculate traits covary with social environment across populations, it is unknown whether individual variation in sperm traits corresponds to natural variation found...

Data from: Adaptive divergence at the margin of an invaded range

Francis Fatah Kilkenny & Laura F. Galloway
Invasive plant species threaten biological communities globally. However, relatively little is known about how evolutionary processes vary over the course of an invasion. To evaluate the importance of historical and adaptive drivers of range expansion, we compare the performance of North American populations of invasive Lonicera japonica from areas established 100-150 years ago, now the southern core of the range, to populations from the northern range margin, established within the last 65 years. Growth and...

Data from: Determinants of genetic structure in a nonequilibrium metapopulation of the plant Silene latifolia

Peter D. Fields & Douglas R. Taylor
Population genetic differentiation will be influenced by the demographic history of populations, opportunities for migration among neighboring demes and founder effects associated with repeated extinction and recolonization. In natural populations, these factors are expected to interact with each other and their magnitudes will vary depending on the spatial distribution and age structure of local demes. Although each of these effects has been individually identified as important in structuring genetic variance, their relative magnitude is seldom...

Data from: Experimentally decoupling reproductive investment from energy storage to test the functional basis of a life-history tradeoff

Robert M. Cox, Matthew B. Lovern & Ryan Calsbeek
The ubiquitous life-history trade-off between reproduction and survival has long been hypothesized to reflect underlying energy-allocation trade-offs between reproductive investment and processes related to self-maintenance. Although recent work has questioned whether energy-allocation models provide sufficient explanations for the survival cost of reproduction, direct tests of this hypothesis are rare, especially in wild populations. This hypothesis was tested in a wild population of brown anole lizards (Anolis sagrei) using a two-step experiment. First, stepwise variation in...

Data from: Synchronous effects produce cycles in deer populations and deer-vehicle collisions

Thomas Anderson, Lawrence Sheppard, Jon Walter, Robert Rolley & Dan Reuman
Population cycles are fundamentally linked with spatial synchrony, the prevailing paradigm being that populations with cyclic dynamics are easily synchronized. That is, population cycles help give rise to spatial synchrony. Here we demonstrate this process can work in reverse, with synchrony causing population cycles. We show that timescale-specific environmental effects, by synchronizing local population dynamics on certain timescales only, cause major population cycles over large areas in white-tailed deer. An important aspect of the new...

Rapid reversal of a potentially constraining genetic covariance between leaf and flower traits in Silene latifolia

Janet Steven, Ingrid Anderson, Edmund Brodie & Lynda Delph
Genetic covariance between two traits generates correlated responses to selection, and may either enhance or constrain adaptation. Silene latifolia exhibits potentially constraining genetic covariance between specific leaf area and flower number in males. Flower number is likely to increase via fecundity selection but the correlated increase in specific leaf area increases mortality, and specific leaf area is under selection to decrease in dry habitats. We selected on trait combinations in two selection lines for four...

Self-organising cicada choruses respond to the local sound and light environment

Lawrence Sheppard, Brandon Mechtley, Jonathan Walter & Daniel Reuman
1. Periodical cicadas exhibit an extraordinary capacity for self-organising spatially synchronous breeding behavior. The regular emergence of periodical cicada broods across the US is a phenomenon of longstanding public and scientific interest, as the cicadas of each brood emerge in huge numbers and briefly dominate their ecosystem. During the emergence, the 17-year periodical cicada species Magicicada cassini is found to form synchronised choruses, and we investigated their chorusing behavior from the standpoint of spatial synchrony....

Data from: Randomized phase 2 study of FcRn antagonist efgartigimod in generalized myasthenia gravis

James F. Howard, Vera Bril, Ted M. Burns, Renato Mantegazza, Malgorzata Bilinska, Andrzej Szczudlik, Said Beydoun, Francisco Javier Rodriguez De Rivera Garrido, Fredrik Piehl, Mariarosa Rottoli, Philip Van Damme, Tuan Vu, Amelia Evoli, Miriam Freimer, Tahseen Mozaffar, E. Sally Ward, Torsten Dreier, Peter Ulrichts, Katrien Verschueren, Antonio Guglietta, Hans De Haard, Nicolas Leupin & Jan J. G. M. Verschuuren
Objective: To investigate safety and explore efficacy of efgartigimod (ARGX-113), an anti-neonatal Fc receptor immunoglobulin G1 Fc fragment, in patients with generalized myasthenia gravis (gMG) with a history of anti-acetylcholine receptor (AChR) autoantibodies, who were on stable standard-of-care myasthenia gravis (MG) treatment. Methods: A phase 2, exploratory, randomized, double-blind, placebo-controlled, 15-center study is described. Eligible patients were randomly assigned (1:1) to receive 4 doses over a 3-week period of either 10 mg/kg IV efgartigimod or...

Data from: Systems analysis of adaptive responses to MAP Kinase pathway blockade in BRAF mutant melanoma

Brian J. Capaldo, Devin Roller, Mark J. Axelrod, Alex F. Koeppel, Emanuel F. Petricoin, Craig L. Slingluff, Michael J. Weber, Aaron J. Mackey, Daniel Gioeli & Stefan Bekiranov
Fifty percent of cutaneous melanomas are driven by activated BRAFV600E, but tumors treated with RAF inhibitors, even when they respond dramatically, rapidly adapt and develop resistance. Thus, there is a pressing need to identify the major mechanisms of intrinsic and adaptive resistance and develop drug combinations that target these resistance mechanisms. In a combinatorial drug screen on a panel of 12 treatment-naïve BRAFV600E mutant melanoma cell lines of varying levels of resistance to mitogen-activated protein...

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