54 research outputs found
The effect of fire on ant assemblages does not depend on habitat openness but does select for large, gracile predators
Ecosystems can respond in a variety of ways to the same agent of disturbance. In some contexts,
fire causes large and long-lasting changes to ecological communities. In others, fire has a limited or
short-lived impact on assemblages of animals and plants. Understanding why this occurs is critical if we
are to manage these kinds of disturbances across the globe. A recent synthesis proposed that these seemingly
idiosyncratic responses to fire can be understood in the context of habitat openness pre-disturbance.
Assemblages in open habitats should respond less to a single fire event that those in closed habitats. We
provide a test of this hypothesis by examining the response of ant (Hymenoptera: Formicidae) communities
to large-scale fire events in three habitats of different natural canopy openness on the Peloponnese
peninsula in Greece. We also test the hypothesis that assemblage responses to fire are trait dependent. Fire
simplifies the physical structure of the environment, increases insolation, and limits opportunities for ants
to exploit herbivorous feeding strategies. Consequently, we predict that ants will face a strong environmental
filter between unburnt and recently burnt plots, which will be reflected in their functional morphology.
Our analysis shows that burnt plots have more individual ants, more species and an almost complete compositional
change relative to unburnt plots. These changes do not depend on initial canopy openness.
Rather, we suggest that openness must be interpreted relative to the study taxon; for ants, openness should
be measured closer to the ground level. In our study, ground-level openness does not vary across the plots,
which may explain the results. Furthermore, ants in burnt plots are significantly larger, have relatively
longer legs, relatively longer mandibles, and more elongate heads. This morphotype fits with our prediction
of ants that can move and feed successfully in the burnt micro-landscape. Ultimately, more work is
needed to fully explore the relationship between habitat openness and the response to fire. Our results
showing a filtered set of ant morphologies in burnt environments suggest that ant traits may offer a further
way forward to understand the faunal response to fire and disturbance in general.http://www.esajournals.org/loi/ecspam2022Zoology and Entomolog
Flexible polyandry in female flies is an adaptive response to infertile males
Infertility is common in nature despite its obvious cost to individual fitness. Rising global temperatures are predicted to decrease fertility, and male sterility is frequently used in attempts to regulate pest or disease vector populations. When males are infertile, females may mate with multiple males to ensure fertilization, and changes in female mating behavior in turn could intensify selection on male fertility. Fertility assurance is a potentially wide-spread explanation for polyandry, but whether and how it actually contributes to the evolution of polyandry is not clear. Moreover, whether a drop in male fertility would lead to a genetic increase in polyandry depends on whether females respond genetically or through behavioral plasticity to male infertility. Here, we experimentally manipulate male fertility through heat-exposure in Drosophila pseudoobscura, and test female discrimination against infertile males before and after mating. Using isogenic lines, we compare the roles of behaviorally plastic versus genetically fixed polyandry. We find that heat-exposed males are less active and attractive, and that females are more likely to remate after mating with these males. Remating rate increases with reduced reproductive output, indicating that females use current sperm storage threshold to make dynamic remating decisions. After remating with fertile males, females restore normal fecundity levels. Our results suggest that male infertility could explain the evolution of adaptively flexible polyandry, but is less likely to cause an increase in genetic polyandry
DNA repair. PAXX, a paralog of XRCC4 and XLF, interacts with Ku to promote DNA double-strand break repair.
XRCC4 and XLF are two structurally related proteins that function in DNA double-strand break (DSB) repair. Here, we identify human PAXX (PAralog of XRCC4 and XLF, also called C9orf142) as a new XRCC4 superfamily member and show that its crystal structure resembles that of XRCC4. PAXX interacts directly with the DSB-repair protein Ku and is recruited to DNA-damage sites in cells. Using RNA interference and CRISPR-Cas9 to generate PAXX(-/-) cells, we demonstrate that PAXX functions with XRCC4 and XLF to mediate DSB repair and cell survival in response to DSB-inducing agents. Finally, we reveal that PAXX promotes Ku-dependent DNA ligation in vitro and assembly of core nonhomologous end-joining (NHEJ) factors on damaged chromatin in cells. These findings identify PAXX as a new component of the NHEJ machinery.T.O. and T.L.B. are supported by the Wellcome Trust. The Jackson lab is funded by Cancer
Research UK (CRUK) program grant C6/A11224, the European Research Council and the
European Community Seventh Framework Programme grant agreement no. HEALTH-F2-2010-
259893 (DDResponse). Core infrastructure funding to the Jackson lab is provided by CRUK
(C6946/A14492) and the Wellcome Trust (WT092096). S.P.J. receives his salary from the
University of Cambridge, supplemented by CRUK. V.M.D. is a CRUK Career Development Fellow. The Draviam lab is funded by a CRUK CDA (C28598/A9787).This is the accepted manuscript version. The final version is available from AAAS at http://www.sciencemag.org/content/347/6218/185.full
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A naval damage incident recoverability toolset: Assessing naval platform recoverability after a fire event
Naval platform survivability is a key enabler to ensure maritime warfighting capability. Therefore, assessment of naval platform recoverability, after a damage event, is critical to assure platform survivability in a warfighting environment. To support such an assessment, an innovative modelling and simulation capability, known as the Naval Damage Incident Recoverability Toolset (NavDIRecT) is being developed. NavDIRecT is being designed as a component-based, open architecture providing the necessary framework to allow analysts to integrate domain models of their choosing. NavDIRecT will facilitate analysis of warfighting and peacetime damage events using a variety of mathematical models, thereby avoiding the limitations of other survivability assessment techniques. Development of NavDIRecT is exemplified by integrating the human movement simulator, maritimeEXODUS, the fire simulation environment, SMARTFIRE, and a three-dimensional naval platform model. NavDIRecT will enable analysis of crew interaction with damage events, thereby allowing acquisition programs and mission planners to examine platform survivability with respect to mission capability requirements. The impetus for NavDIRecT development is for assessment of naval platform survivability and mission success; however, the tools and techniques are equally suitable for use in incident management, training, and analysis of merchant and commercial shipping in accordance with the Safety of Life at Sea (SOLAS)
Family Structure and Voter Turnout
Abstract We use data from the Voting and Registration Supplement of the Current Population Survey to explore the effects of family structure on turnout in the 2000 presidential election. Our results indicate that family structure, defined as marital status and the presence of children, has substantial consequences for turnout. Married adults are more likely to vote than are those who have never been married; in turn, previously married people are the lightest voters. Children have a smaller but still noteworthy effect on turnout. These results are only partially explained by social and demographic differences
Everything Matters: The ReproNim Perspective on Reproducible Neuroimaging
There has been a recent major upsurge in the concerns about reproducibility in many areas of science. Within the neuroimaging domain, one approach is to promote reproducibility is to target the re-executability of the publication. The information supporting such re-executability can enable the detailed examination of how an initial finding generalizes across changes in the processing approach, and sampled population, in a controlled scientific fashion. ReproNim: A Center for Reproducible Neuroimaging Computation is a recently funded initiative that seeks to facilitate the “last mile” implementations of core re-executability tools in order to reduce the accessibility barrier and increase adoption of standards and best practices at the neuroimaging research laboratory level. In this report, we summarize the overall approach and tools we have developed in this domain
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Genome-Wide Association Identifies Nine Common Variants Associated With Fasting Proinsulin Levels and Provides New Insights Into the Pathophysiology of Type 2 Diabetes
OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10−8). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10−4), improved β-cell function (P = 1.1 × 10−5), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10−6). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis
New genetic loci link adipose and insulin biology to body fat distribution.
Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms
Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.
OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis
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