In many plant species, FLOWERING LOCUS T and related proteins are the mobile signal that communicates information on photoperiod from the leaves to the shoots, where the transition to flowering is realized. FT expression is tightly controlled at the transcriptional level so that it is restricted to leaves, occurs only in appropriate photoperiods, and integrates ambient temperature and developmental cues, as well as information on biotic and abiotic stress. We previously established that FT transcription in the model plant Arabidopsis thaliana requires proximal promoter cis-elements and a distal enhancer, both evolutionary conserved among Brassicacea species. In addition, FT transcription is blocked prior vernalization in biannual accessions and vernalization-dependency of FT is controlled through a CArG-box located in the first intron that binds the transcriptional repressor FLOWERING LOCUS C (FLC). Chromatin-mediated repression by the Polycomb Group (PcG) pathway is required for photoperiod-dependent FT regulation and participates in FT expression level modulation in response to other cues.In this project, I propose to explore the available sequence data from the 1001 genome project in Arabidopsis to evaluate how often changes in regulatory cis-elements at FT have occurred and how these translate into an adaptive value. Allele-specific FT expression pattern will be measured in F1 hybrids of different accessions in response to varying environmental conditions. FT alleles that show cis-regulatory variation will be further analyzed to pinpoint the causal regulatory changes and study their effect in more detail. The allotetrapolyploid species Brassica napus is a hybrid of two Brassiceae species belonging to the A- and C-type genome, which are in turn mesopolyploid due to a genome triplication that occurred ca. 10x106 years ago. We will determine allele-specific expression of FT paralogs from both genomes of a collection of B. napus accessions. The plants will be grown in the field in changing environmental conditions to maximize the chance to detect expression variation of the paralogs. We will compare the contribution of the founder genomes to the regulation of flowering time and asses variation in this contribution. A particular focus will be to study the impact of chromatin-mediated repression on allele selection in B. napus.
In my project I aim at a better understanding of the evolution of malacostracan crustaceans, which includes very different groups such as mantis shrimps, krill and lobsters. Previous studies on Malacostraca, on extant as well as on fossil representatives, focussed on adult morphology.In contrast to such approaches, I will apply a Palaeo-Evo-Devo approach to shed new light on the evolution of Malacostraca. Palaeo-Evo-Devo uses data of different developmental stages of fossil malacostracan crustaceans, such as larval and juvenile stages. With this approach I aim at bridging morphological gaps between the different diverse lineages of modern malacostracans by providing new insights into the character evolution in these lineages.An extensive number of larval and juvenile malacostracans is present in the fossil record, but which have only scarcely been studied. The backbone of this project will be on malacostracans from the Solnhofen Lithographic Limestones (ca. 150 million years old), which are especially well preserved and exhibit minute details. During previous studies, I developed new documentation methods for tiny fossils from these deposits, e.g., fluorescence composite microscopy, and also discovered the first fossil mantis shrimp larvae. For malcostracan groups that do not occur in Solnhofen, I will investigate fossils from other lagerstätten, e.g., Mazon Creek and Bear Gulch (USA), or Montceaules- Mines and La-Voulte-sur-Rhône (France). The main groups in focus are mantis shrimps and certain other shrimps (e.g., mysids, caridoids), as well as the bottom-living ten-footed crustaceans (reptantians). Examples for studied structures are leg details, including the feeding apparatus, but also eyes. The results will contribute to the reconstruction of 3D computer models.The data collected in this project will be used for evaluating the relationships within Malacostraca, but mainly for providing plausible evolutionary scenarios, how the modern malacostracan diversity evolved. With the Palaeo-Evo-Devo approach, I am also able to detect shifts in developmental timing, called heterochrony, which is interpreted as one of the major driving forces of evolution. Finally, the reconstructed evolutionary patterns can be compared between the different lineages for convergencies. These comparisons might help to explain the convergent adaptation to similar ecological niches in different malacostracan groups, e.g., life in the deep sea, life on the sea bottom, evolution of metamorphosis or of predatory larvae.As the project requires the investigation of a large number of specimens in different groups, I will assign distinct sub-projects to three doctoral researchers. The results of this project will not only be published in peer-reviewed journals, but will also be presented to the non-scientific public, e.g., during fossil fairs or museum exhibitions with 3D models engraved in glass blocks.
In addition to recognizing natural selection as a universal mechanism in evolution, Darwin also saw the importance of sexual selection, yet the two have been traditionally treated largely in isolation. Here I propose to apply experimental evolution (exposing experimental populations to controlled specific selective pressures over many generations in the laboratory) to the ideally suited model system Tribolium castaneum to explore how these evolutionary forces interact and impact on the key processes underlying biodiversity. Understanding how these fundamental forces, singly and in conjunction, influence species divergence remains a major challenge in evolutionary biology. Participation of sexual selection in driving speciation is supported by substantial theoretical evidence. Theory further suggests that evolutionary conflicts (such as between the sexes or between host and parasite) might also accelerate extinction. Additional complexity is introduced by including the environmental context, linking back to natural selection. Direct experimental tests of the above concepts are essentially lacking. I will explicitly target this gap by exploiting powerful experimental evolution, incorporating the interplay between sexual selection intensity, host-parasite conflict, and adaptation to increasing temperature. Projects will assess how selection under evolutionary conflict and environmental change affects both adaptation and extinction rates, aiming to elucidate underlying mechanisms. Additionally, building on clear phenotypic divergence in key traits across experimental evolution lines, I will significantly expand on previous work by assessing patterns of divergence in gene expression, concentrating on target genes associated with reproduction, immunity and heat shock. This research will be of particular interest to scientists working in the fields of evolutionary biology and behavioural ecology, but also to ecologists, reproductive biologists, and conservation biologists. As Tribolium beetles are widespread agricultural pests, results will also be relevant to more applied researchers.
Natural populations are increasingly exposed to extreme environmental changes as a result of human activities. These changes threaten the existence of populations and cause strong natural selection at short time-scales. In the long term, the persistence of populations is determined by their capacity to respond to this selection via genetic adaptation. It is therefore crucial to understand how evolutionary processes influence the ability of populations to cope with the ongoing environmental changes. This project focuses on studying two major factors that influence the ability of populations to adapt to rapid environmental change: gene flow (movement of genes resulting from dispersal of individuals) and maternal effects (the effects of a mother's traits that, in addition to offspring's own genes, affect offspring performance), both of which have the potential to either impede or speed up adaptation. On this vein, the proposed research focuses in particular on understanding how gene flow and maternal effects affect the ability of populations to adapt to environmental changes. The main part of the research will be conducted on Swedish populations of the moor frog (Rana arvalis) that inhabit areas affected to different extents by human-induced acidification. The main questions to be targeted are i) to what extent is the level of local adaptation to acidification explained by variation in the extent of gene flow or variation in the strength of selection among populations, ii) how wide-spread are maternal effects as adaptations and iii) how is maternally determined local adaptation maintained in the face of gene flow? Because experimental manipulations are not possible in these natural populations, related questions will in parallel be addressed in a pilot study on laboratory populations of Daphnia. Here the main questions to be targeted are i) under which conditions does gene flow have positive vs. negative effects on adaptation to novel environments and ii) how do maternal effects influence the ability to respond genetically to rapid environmental changes? Different complementary approaches will be used in the different subprojects to allow rigorous inferences and predictions. The main methods to be used include large-scale geographic sampling (for environmental, molecular genetic, and phenotypic variation) and mark-recapture studies in nature, molecular and quantitative genetic analyses in the laboratory, and fitness assays in semi-natural and laboratory conditions. The results from this research will illustrate to what extent gene flow and maternal effects influence variation in the phenotypes that we see in nature, and how they can affect the ability of organisms to adapt to novel environments. Ultimately this research aims at understanding the short-term ecological and evolutionary processes that create, maintain and change biological diversity, and will be of broad significance for evolutionary biology as well as conservation biology.
For effective crop improvement, breeders must be able to select on relevant phenotypic traits without compromising yield. This project proposes to investigate the evolutionary consequences of flowering time modifications on a second trait of major importance for plant breeding: immunity. This will have implications both for understanding cross-talks between flowering time and defense network and for developing efficient breeding strategies. There is clear evidence that plant maturity influences levels and effectiveness of defense. Theoretical models actually predict that changes in life-history can modulate the balance between costs and benefits of immunity. Simultaneously, actors of the immune system have often been observed to alter flowering time. Two alternative and possibly complementary hypotheses can explain this link: genetic constraints due to the pleiotropic action of players in either systems, or co-evolution, if flowering-time changes modulate the cost-benefit balance of immunity. We will conduct field assays in Arabidopsis thaliana, using constructed lines as well as recombinant inbred lines and natural accessions, to differentiate the action of the two explanatory hypotheses. Using transcriptome analyses, we will identify defense genes associating with flowering time modification (f-t-a defense genes). We will quantify their expression along the assay and test whether it varies with both flowering time and fitness. We will further test whether flowering time and immunity interact to determine yield in tomato and potato.
The project will use analysis of long-term data, resurrection ecology and modeling to investigate the ecological and evolutionary response of an aquatic key herbivore, Daphnia, to environmental change. In addition, the results obtained will enable to estimate the consequences of the evolutionary response of Daphnia for its population dynamics, persistence and consequently, overall ecosystem dynamics. The project will analyze in detail the response of Daphnia, its food, competitors and predators to oligo-trophication in a model ecosystem, i.e., Lake Constance and additionally variability in Daphnia population dynamics in several of the best studied lakes of the world. Historical field samples from Lake Constance will be re-analyzed to study the phenotypic life history and morphological responses of Daphnia to oligo-trophication. Using resurrection ecology we will analyze the evolutionary response of Daphnia galeata life history parameters to oligo-trophication - with special emphasis on its investment into sexual reproduction/production of resting eggs as well as life history plasticity in response to invertebrate predators and declining food levels. These analyses (in combination with model simulations) will provide key data for understanding the role of Daphnia life cycle strategy (overwintering in the plankton or in resting eggs) for Daphnia persistence in permanent lakes, for the interpretation of Daphnia resting egg banks, and the evolution of the genetic variances and co-variances of life history parameters.
Enzyme der Peroxidase-Cyclooxygenase Superfamilie katalysieren biochemische Reaktionen, die in unzähligen biologischen Prozessen eine wichtige Rolle spielen, z.B. bei der unspezifischen Immunabwehr, der Synthese der Schilddrüsenhormone oder der Bildung und Modifizierung der extrazellulären Matrix. Sie sind zudem auch bei der Pathogenese von chronischen entzündlichen Erkrankungen beteiligt. In der Subfamilie 2 dieser Superfamilie findet man Multidomänen-Oxidoreduktasen, sog. Peroxidasine (Pxds). Hierbei handelt es sich um glykosylierte und sekretierte Häm-Peroxidasen, die zusätzlich zur katalytischen Domäne sog. Leucin-reiche Wiederholungssequenzen, Immunoglobulin C-ähnliche Domänen sowie von Willebrandfaktor C enthalten. Diese Strukturmotive finden sich in vielen extrazellulären Molekülen, die mit anderen Proteinen in Wechselwirkung treten. Ursprünglich wurde Peroxidasin in Basalmembranen von Drosophila entdeckt. Spätere Arbeiten zeigten, dass diese Enzyme auch in Wirbeltieren vorkommen und eine Rolle bei der unspezifischen Immunabwehr, der Gewebsbildung, Ausbreitung von Tumoren und oxidativen Prozessen eine Rolle spielen. Kürzlich wurde gezeigt, dass dieses Metallprotein mit Hilfe von Hypohalogeniten im Kollegen IV für die Bildung von kovalenten Kohlenstoff-Stickstoffbindungen verantwortlich ist, ein Prozess, der sowohl bei der Gewebsbildung als auch bei zahlreichen Kranksheitsbildern eine wichtige Rolle spielt. Trotz der physiologischen Bedeutung dieser neuen Proteinfamilie ist das biochemische Wissen sehr bescheiden. In diesem Projekt sollen daher, basierend auf umfangreichen phylogenetischen Voranalysen und der bereits erfolgreich durchgeführten rekombinanten Produktion von humanem Peroxidasin 1 in tierischen Zellkulturen, die Struktur-Funktionsbeziehungen von vier Peroxidasinen unterschiedlicher Entwicklungsstufe und Sequenz analysiert werden: Peroxidasin 1 von Caenorhabditis elegans, Pxd von Drosophila melanogaster als auch die beiden humanen Peroxidasine 1 & 2. Basierend auf der rekombinanten Produktion der vier Modell-Proteine in voller Kettenlänge bzw. von verkürzten Varianten unterschiedlicher Domänenzusammensetzung werden umfangreiche bio-chemische/biophysikalische Analysen durchgeführt: (i) UV-vis-, Fluoreszenz- CD-, Lichtstreuung-, RR- und ESR-Spektroskopie, (ii) Stopped-flow-Spektroskopie und Polarographie, (iii) MS und Röntgenkristallographie, (v) Spektroelektrochemie und (vi) Kalorimetrie. Mit Hilfe dieser Methoden sollen Struktur und Aktivität der Peroxidasine aufgeklärt werden wie z.B. (i) oligomere Struktur und Architektur des aktiven Zentrums, (ii) Interaktion der Domänen und Mechanismen der Proteinentfaltung, (iii) Chemie der prosthetischen Gruppe inklusive Oxidations- und Spinzustände, Häm-Liganden und posttranslationale Modifizierungen, (iv) Spezifität, Zugänglichkeit, und Bindungorte von Substraten als auch chemische Natur der Reaktionsprodukte (v) Chemie, Reaktivität und Relevanz von Redox-Intermediaten und (vi) die Ro
The world is currently experiencing a major biodiversity crisis due to human activities. A primary concern is the on-going and rapid biological consequences of global climate change. Climate change is impacting alpine landscapes at unprecedented rates, with severe impacts on landscape structure and catchment hydrodynamics, as well as temperature regimes of glacial-fed rivers. Most glaciers are expected to be dramatically reduced and many even gone by the year 2100, concomitantly with changes (timing and magnitude) in temperature and precipitation. These environmental changes are predicted to have strong impacts on the persistence and distribution of alpine organisms, their population structure and community assembly, and, ultimately, ecosystem functioning. However, how alpine biodiversity (aquatic macroinvertebrates in our case) will respond to these changes is poorly understood. Most previous studies predict the presence of species based on the distribution of putatively suitable habitats but ignore biotic traits, such as dispersal, and potential eco-evolutionary responses to such changes. Clearly, accurate predictions on species responses require integrative studies incorporating landscape dynamics with eco-evolutionary processes. The primary goal of the proposed research is to empirically test determinants of alpine macroinvertebrate responses to rapid environmental change mediated by glacial recession. Climate-induced glacial retreat is occurring rapidly and in a replicated fashion (i.e. over multiple catchments and continents), which provides a natural experiment for testing determinants of organismal and species diversity responses to climate change in alpine waters. The responses of alpine aquatic macroinvertebrates are highly important because of their known sensitivity (i.e. response rates) to environmental change and their fundamental role in ecosystem functioning. Using an integrative comparative and experimental approach, we will target the following main question: What are the roles of ecological and evolutionary processes in population level responses of macroinvertebrates to environmental change? The study will take advantage of rapid glacial recession (environmental change) to empirically examine spatio-temporal patterns in species distribution in nature, combined with experimental and population genetics approaches. The data generated will be used to explicitly address the role of eco-evolutionary processes (determinants) on population level responses for selected key species. Spatial and temporal variation in species distribution, phenotypic and genetic variation will be quantified for two stream macroinvertebrates (hemimetabolous mayfly Baetis alpinus, holometabolous caddisfly Allogamus uncatus), and measuring landscape features and physico-chemical parameters along longitudinal transects downstream of glaciers and selected side-slope tributaries (as potential stepping stones for dispersal and colonization).
Predictions of effects of climate change on species distributions assume constant climatic niches. Our current understanding of how climate niches developed through evolution is very limited. This project shall analyse how climate niche of the 5488 mammal species worldwide is related to their phylogenetic position. The hypothesis is that closely related species will also have similar climate niches, indicating climate niche conservation. Based on current distributions and environmental data, we shall quantify the climate niche of each species and compare it to that of its closest relative (sister species). We shall investigate whether climate niche position is similarly phylogenetically constrained as other species traits such as body weight, gestation length or litter size. The huge breadth of mammal ecologies, their highly resolved phylogenetic tree, their high conservation relevance and their relatively well-known geographical distribution make them an ideal study system. In the process of this study, new methodological standards for the analysis of niche evolution will be developed, including randomisation tests, virtual species analysis and character tracing of climate niche position. In the end, we shall be able to specify the adaptation potential to climate change for a large number of species studied.
One of the fundamental principles in biology is that evolution by natural selection, and therefore the ability of populations to adapt to changing environments, requires heritable variation, i.e. genetically-based variation in phenotypic traits that are under selection. Until recently, such heritable variation was generally thought to require underlying DNA sequence variation. Thus, populations that lack DNA sequence variation were assumed be unable to evolve. However, there is now increasing evidence that epigenetic modifications of the genome, such as DNA methylation or histone modifications - which regulate gene activity and therefore ultimately the phenotype - can be heritable, too, and that there can be epigenetic variation within and among natural populations which is independent of DNA sequence variation. Moreover, epigenetic variation can sometimes be altered direct by the environment, which suggests that such heritable epigenetic variation might be an important and hitherto overlooked component of biodiversity and an additional mechanism for organisms to respond to environmental change. Our project is part of a larger pan-European project (involving partners from the Netherlands, Germany, Austria and France) that attempts to address these exciting questions about the ecological and evolutionary relevance of epigenetic variation and epigenetic inheritance in several connected sub-projects. In our project, we will test the hypothesis that evolution by natural selection can occur even in the absence of DNA sequence variation, based on heritable epigenetic variation only. We will use selection experiments, and a recently developed, unique set of genotypically near-identical but epigenetically distinct recombinant inbred lines (epiRILs) of Arabidopsis thaliana to study epigenetic evolution 'in action'. The specific objectives of our project are (i) to characterise 100+ epiRILs with regard to their drought and pathogen resistance, (ii) to subject replicated experimental populations of these epiRILs to at least 3-4 generations of natural or artificial selection imposed by experimental drought and/or pathogens, and (iii) to quantify the response to this selection both in terms of phenotypic shifts as well as shifts in epigenotype frequencies.
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