Every semester, EES organise a seminar series, which takes place on Mondays at 16:00 at Biozentrum, Großhaderner Str. 2, 82152 Planegg-Martinsried, Lecture Hall B 01.019
External speakers are invited across all three areas (Evolution, Ecology and Systematics), leading to a wide-range of presented research topics.
Summer Semester 2023
Hannah Rowland - How toxins mediate ecological interactions - C A N C E L L E D
MPI for Chemical Ecology, Jena, Germany
Abstract: My research examines how toxins mediate ecological interactions between plants, herbivores, and predators. My primary study system is centred around toxic steroidal heart poisons produced by milkweed plants. I also have major projects on poison frogs, tiger moths, and snakes. My goal is to understand how multi-trophic interactions lead to evolutionary innovation and diversification. To achieve this I integrate research across different biological levels of organisation, and use multidisciplinary tools from small molecule chemistry, to molecular and cell biology, to whole animal behaviour. I will present my research examining the evolution of – and new adaptations to – toxicity, that has broad implications for the evolutionary dynamics of signalling systems and animal behaviour. My talk will addresses specific evolutionary questions such as the role of epistasis and contingency in molecular evolution, and how novel protein functions arise.
Host: Richard Merrill (email@example.com)
Stuart Baird- Genome Polarisation
IVB, Czech Academy of Sciences, Czech Republic
Abstract: Incomplete barriers to geneflow allow admixed inheritance across, not down the tree of life. This may change the rate of adaptation in times of rapid environmental shifts such as the current climate crisis.To understand this potential requires knowledge of the prevalence of barriers in nature and their barrier strength. Genome polarisation paints genomes with respect to the sides of barriers, and so may help in building this knowledge base.
Host: Jochen Wolf (firstname.lastname@example.org)
Sean Stankowski - Selection on many loci drove the origin and spread of a key innovation
Abstract: Key innovations are fundamental to biological diversification, but their genetic architecture is poorly understood. A recent transition from egg-laying to live-bearing in Littorina snails provides the opportunity to study the architecture of a young innovation. Samples do not cluster by reproductive mode in a genome-wide phylogeny, but local genealogical analysis revealed numerous genomic regions where all live-bearers carry the same core haplotype. Associated regions show evidence for live-bearer-specific positive selection, and are enriched for genes that are differentially expressed between egg-laying and live-bearing reproductive systems. Ages of selective sweeps suggest live-bearing alleles accumulated gradually, involving selection at different times in the past. Our results suggest that innovation can have a polygenic basis, and that novel functions can evolve gradually, rather than in a single step.
Host: Jochen Wolf (email@example.com)
Ivan Kolidarov - Evolution of Functionally Novel Genes: Insights From the Animal Venoms
Abstract: In this talk, we will explore the evolution of novel functions in animals, with a focus on toxins in venomous bees and snakes. We will base our discussion on a combination of genomic and proteomic data, as well as tools such as synteny, phylogenetic and protein space AI analyses that were used to investigate the origin and diversification of toxin-encoding genes. We will delve into the mechanisms of gene duplication and its relationship to the emergence of novel biological functions, illustrating it by the evolution of g2 family of phospholipase A2 in Vertebrata and the 3-finger toxins in caenophidian snakes. Our reconstruction of evolutionary history suggests that duplication events and the resulting functional redundancy have played a significant role in the evolution of these gene families. However, our research also highlights that the evolution of functionally diverse genes is a complex process that is shaped by a variety of historical, genomic, and ecological factors, and that neofunctionalization may not always be the best model to explain the evolution of genetic novelty
Host: Andrea Pozzi (firstname.lastname@example.org)
Daven Presgraves - The roles of selfish genes during complex speciation in Drosophila
University of Rochester, USA and Wissenschaftskolleg zu Berlin, Germany
Abstract: Eukaryotic genomes contain a diversity of evolutionarily “selfish” genetic elements (SGEs) that obtain transmission advantages at the expense of their host carriers. SGEs tend to use one of two broad strategies: over-replicate relative to the host genome (e.g., transposable elements) or distort Mendelian transmission (e.g., meiotic drive elements). Sex chromosomes, it turns out, are especially susceptible to the accumulation of meiotic drive elements that, by distorting X versus Y chromosome transmission, bias progeny sex ratios. Such “sex-ratio drive” potentiates evolutionary conflicts of interest between drivers and drive-suppressors at X-linked, Y-linked, and autosomal loci. Molecular arms races arising from recurrent bouts of sex-ratio drive and suppression can have far reaching consequences for genome evolution and for speciation. In this talk, I will show how a system of sex-ratio drivers & suppressors evolved recently and then rapidly amplified and diversified among three closely related species of Drosophila— D. simulans, D. mauritiana, and D. sechellia. I will discuss how this drive system contributed to the evolution of genetic incompatibility and to the history of gene flow among between species.
Host: John Parsch (email@example.com)
Rahel Sollman- Hierarchical statistical models in wildlife ecology
Leibniz Institute for Zoo and Wildlife Research
Abstract: Hierarchical statistical models (HSM) are multi-level models in which one level is conditional on another. These models are used in a myriad ways, for example, to account for nested sampling designs, to model processes on multiple scales (e.g., spatial or temporal), or to disentangle ecological from observation processes. The latter is particularly important in wildlife research, as animals are notoriously difficult to observe. As a result, ecological state variables of interest, such as species presence or abundance, are observed imperfectly, e.g., a species may be present but never detected by sampling; or a population may consist of more individuals than are counted. In my talk, I will provide an overview over HSM that address this form of observation bias, also called imperfect detection, by describing an observation model that is conditioned on the true, but latent, underlying ecological state. I will present occupancy models, in which repeated species-level detection/non-detection data collected across multiple sites (observation) are used to estimate species occurrence (ecological state) while accounting for imperfect species detection, and which are often fit to joint data from multiple species (i.e., community occupancy models). I will touch on count-based models to estimate abundance, with a focus on distance sampling, in which individual detection probability is described as a declining function of distance from the observer, allowing for estimation of abundance (ecological state) from counts (observations). Finally, I will discuss traditional and spatial capture-recapture, the gold standard of abundance estimation, based on repeated detection data of animals that can be identified individually, through natural or artificial marks. I illustrate all approaches with case studies that also showcase extensions to the basic models. Overall, HSM is a flexible framework that can be tailored to specific sampling circumstances to investigate spatio-temporal processes in wildlife ecology while addressing imperfect detection.
Host: Richard Merrill (firstname.lastname@example.org)
Andreas Fleischmann - Food, sex and crime: interactions between carnivorous plants and insects
Botanische Staatssammlung München
Host: Gundrun Kandereit (G.Kadereit@biologie.uni-muenchen.de)
Markus Möst - The multifarious outcomes of hybridization and the consequences of life cycle variation
University of Innsbruck
Abstract: Hybridization and introgression are now recognized as important evolutionary processes that can facilitate speciation and rapid adaptation to new environments. However, a hybridization event may have various outcomes and may range from a collapse of species into a hybrid swarm, over hybrid speciation and adaptive introgression to a complete removal of hybrids and purging of introgressed alleles via intrinsic or extrinsic forces that may eradicate the traces of a hybridization event and contribute to the maintenance of stable specie boundaries. The results of a secondary contact may even differ within the same pair of species, for example along an extended contact zone or among multiple contact zones. Factors affecting the outcome and dynamics of hybridization include spatial heterogeneity and – often underappreciated – features of species’ life cycles, such as cyclical parthenogenesis or propagule banks. I will contrast different outcomes of hybridization and the role of life cycle in the Heliconius butterflies and a hybridizing Daphnia water flea species complex. I will highlight a few intriguing cases of adaptive introgression in Heliconius butterflies and continue with recent work leveraging whole-genome time series obtained from Daphnia resting eggs deposited in lake sediments reconstructing recent cases of secondary contact and interspecific hybridization following anthropogenic habitat disturbance through cultural eutrophication in European peri-Alpine lakes. Despite periods of extensive hybridization and extended backcrossing during ecological transitions, the parental species still exist as distinct units alongside hybrid lineages. I will discuss possible mechanisms reducing the impact of hybridization and highlight the role and interaction of life cycle features and spatio-temporal ecological heterogeneity in maintaining species boundaries in this hybridizing species complex. To conclude, I will discuss ongoing work studying the consequences of hybridization in a keystone species for its community and ecosystem.
Host: Richard Merrill (email@example.com)
Melanie Dammhahn - University of Münster, Germany
Winter Semester 2022/23
Cristina Tuni -Reproductive trait evolution: unravelling the effects of pre- and post-copulatory sexual
selection. (ONLINE ONLY)
University of Torino, Italy
Abstract: Sexual selection operates both before and after mating, with evolutionary theory predicting that traits involved in mate acquisition, namely pre-copulatory traits, covary with those involved in fertilization success, namely post-copulatory traits. Based on the nature of these associations, selection acting on traits, such as male ornaments and/or armaments, can potentially constrain or facilitate the evolution of other traits, such as testes and/or sperm phenotype, and vice-versa. Using the field cricket Gryllus bimaculatus as a model system, my research aims at understanding how pre- and post-copulatory sexual selection shape complex reproductive phenotypes. I will
discuss findings from studies uncovering both, phenotypic and genetic correlations among behaviour, morphology, and ejaculate traits, suggesting that traits are integrated at the genetic level. I will further report on a long-
term experimental evolution study designed to disentangle the effects of pre-and post-copulatory selective pressures on a range of reproductive traits. The study of male courtship singing, aggressiveness and weaponry (mandibles), testes and sperm traits, will allow understanding whether and which traits diverge in response to altered pre- or post-mating selective pressures, potentially shedding light on correlated evolution and/or evolutionary trade-offs between reproductive traits.
R. Brian Langerhans - Predictability and parallelism of multi-trait adaptation and speciation.
North Carolina State University, United States of America
Abstract: Environments shape the traits of organisms and appear to ultimately cause the majority of speciation on Earth. While the deterministic action of selection on organismal phenotypes is widespread, the degree to which evolutionary change might be predicted (from theory) and the magnitude of parallelism (consistent occurrences) during evolution is not yet well understood. Using the post-Pleistocene radiation of Bahamas mosquitofish (Gambusia hubbsi) inhabiting blue holes, I assess the predictability, parallelism, and magnitude of evolutionary divergence in nearly 100 traits and six reproductive isolating barriers. Natural selection clearly drives a non-trivial amount of
predictable and repeatable evolution, directly influencing the evolution of multiple isolating barriers during speciation. But just how predictable and consistent are these patterns, how generalizable are the results, and what explains all of the “unexplained” phenotypic evolution and reproductive isolation?
Carolin Haug -Quantifying convergent evolution: examples from “flying crustaceans”
LMU Munich, Germany
Abstract: Animal life appears almost unlimited in overall form variation,yet we see repetitively the same shapes evolving independently. This phenomenon is generally addressed as convergence. Besides the fact that convergence is widely recognised as “similar morphologies in distantly related lineages”, the question often remains: how similar is similar? I present several cases of convergence within the group Insecta
using quantifiable characteristics of specimens from the modern fauna and the fossil record. Especially apparent are
similar morphologies due to similar selective pressures for grasping and holding prey items. I demonstrate that using
fossil and extant representatives of numerous distantly related lineages in a frame of quantifiable traits offers the detection of cases of convergent evolution and evolutionary processes behind it.
Anja Hörger -Constraint or opportunity? How trade-offs in stress adaptation may facilitate the evolution of heavy metal hyperaccumulation in plants
Paris-Lodron-University Salzburg, Austria
Abstract: Metal hyperaccumulating plants are able to accumulate exceptionally high concentrations of heavy metals in their shoots to levels that would be toxic to most other plant species. This trait has evolved independently multiple times in the plant kingdom. Although our understanding of the molecular mechanisms involved in metal uptake and tolerance has improved, not much is known about the processes that have led to the evolution of metal hyperaccumulation in plants. Recent studies have provided new insight into the ecological
and evolutionary significance of this trait by showing that the metal hyperaccumulatingplant Noccaea caerulescens can use high concentrations of accumulated metals to defend itself against attack by pathogenic microorganisms and/or herbivores. Interestingly, attacked N. caerulescens plants seem compromised in the inducible defence responses that are used by most plants to provide protection against antagonists, which suggests that it
relies on accumulated metal for resistance. The fact that these plants have evolved the ability to uptake and store metals in their shoot tissue, but have in turn lost defences common to most plants suggests a trade-off in expressing both traits. We studied physiological, molecular and ecological processes involved in the gain of metal
hyperaccumulation and loss of other defensive traits in N. caerulescens. Genes involved in the trade-off were identified and analysed using a combined phenotyping and transcriptomics strategy. Our results provide new insights into the evolution and ecology of metal hyperaccumulation and contribute to the understanding of how plant adaptation to biotic and abiotic stress may be connected.
Aurélien Tellier - Inference of ecological and life-history traits from full genome polymorphism data: tales of success and limitations
Technical University of Munich, Germany
Abstract: While most inference methods using full-genome data can be applied to all possible kind of species, the underlying assumptions are often sexual reproduction in each generation and non-overlapping generations. However, in many plants, invertebrates, fungi and other taxa, those assumptions are often violated due to different ecological and life history traits, such as self-fertilization, long term dormant structures (seed or egg-banking) or large
variance in offspring production. Furthermore, the resolution of past inference decreases when there is a lack of SNPs in the data. I will present here three new developments of the Sequentially Markovian Coalescent (SMC) and Deep Learning (DL) methods based on Graph Neural Networks (GNN) allowing us to 1) infer seed banking / dormancy or selfing rates and their change in time, 2) infer the variance in offspring production and regions under positive selection along the genome, and 3) integrate epigenetic (methylation) markers to improve the inference of past events.
Krushnamegh Kunte - The Evolution and Genetics of Butterfly Wing Colour Patterns
National Center for Biological Sciences, Bangalore, India
Abstract: Butterflies use colours in many aspects of their lives: from keeping warm in cold climates to evading predators and impressing potential mates. In this talk, Dr. Kunte will narrate scientific discoveries on how butterfly colour patterns have diversified under natural and sexual selection, how genetic variation and genomic architecture facilitate colour pattern diversification, and how the patterns are regulated during development through co-option and other means. Thus, this talk will bring to the audience a unique appreciation of the evolutionary patterns and genetic mechanisms by which butterflies get their brilliant colours.
Summer Semester 2020
Björn Benning - Bryozoa in a nutshell: evolution, ecology, systematics
Oberösterreichisches Landmuseum Linz, Austria
Virginie Courtier-Orgogozo - Evolution of Drosophila Bristles
CNRS, Paris, France
Douglas Sheil - Forests and Water: Advances and Controversies
Norwegian University of Life Sciences
University of Cambridge, UK
Winter Semester 2019/20
Alistair McGregor - Investigating the Evolution of Developmental Regulation in Spiders and Flies
Oxford Brookes University, UK
Abstract: Research in my lab focuses on questions that are key to understanding animal evolution: How does the genetic regulation of development evolve and what is the genetic and developmental bases for morphological variation within and between species. To address these questions we study the genomics and genetics of the development of the spider Parasteatoda tepidariorum, and gene regulation and morphological evolution among flies of the Drosophila melanogaster species subgroup. In this talk I will present our recent work on the regulation of segmentation in Parasteatoda, and on investigating cis-regulatory logic and morphology evolution among Drosophila species. Research in my lab focuses on questions that are key to understanding animal evolution: How does the genetic regulation of development evolve and what is the genetic and developmental bases for morphological variation within and between species. To address these questions we study the genomics and genetics of the development of the spider Parasteatoda tepidariorum, and gene regulation and morphological evolution among flies of the Drosophila melanogaster species subgroup. In this talk I will present our recent work on the regulation of segmentation in Parasteatoda, and on investigating cis-regulatory logic and morphology evolution among Drosophila species.
Marie Herbestein - Unlocking the paradox of imperfect mimicry using ant mimicking spiders
Macquarie University, Australia
Abstract: Batesian mimics are deliciously palatable species that gain protection from a predator by resembling a defended or unpalatable model. Theory predicts that mimics that closely resemble their model should have the greatest advantage, while inaccurate mimics should be recognised and attacked by predators. This is all fine and good, but in reality, we find that mimics are highly variable, some are excellent in mimicking their model and others are rubbish at it. There are many different hypotheses that try to explain the persistence of inaccurate mimics, and we have a research project at Macquarie University that tests these ideas using ant mimicking spiders. In this seminar, I will illustrate the range of mimic fidelity in ant mimicking spiders and present the evaluation of some of the common hypotheses. If time and technology permits we will even play an online game.
Julien Gagneur - Modelling the regulatory code: From basic biology to clinical research
Technical University of Munich, Germany
My lab is interested in understanding how gene expression is encoded in genomes, and how to leverage this knowledge for medical application. To this end, we employ statistical modeling of ‘omics data and work in close collaboration with experimentalists. I will provide an overview of recent studies on RNA metabolism and protein expression control and on deep learning based models of cis-regulatory elements. I will also report on methodologies for using RNA-sequencing as a powerful companion tool to genome sequencing for pinpointing causes of rare genetic disorders.
Aurelien Tellier -Inference of past demography and life history traits from whole genome genetic and epigenetic data
Technical University of Munich, Germany
Several methods based on the Sequential Markovian coalescence (SMC) have been developed to use full genome sequence data to uncover population demographic history, which is of interest in its own right and is a key requirement to generate a null model for selection tests. While these methods can be applied in principle to all possible species, they have two main limitations: 1) the underlying assumptions are sexual reproduction at each generation and no overlap of generations, and 2) the inference accuracy depends on the ratio of recombination to mutation. However, in many plants, invertebrates, fungi and other taxa, these assumptions are often violated due to different ecological and life history traits, such as self-fertilization, long term dormant structures (seed or egg-banking) or large variance in offspring production. In this presentation I will first describe a novel SMC-based method which we developed to infer 1) the rates of seed/egg-bank and of self-fertilization, and 2) the populations' past demographic history. Using simulated data sets, we demonstrate the accuracy of our method for a wide range of demographic scenarios and for sequence lengths from one to 30 Mb using four sampled genomes. As a test, we apply our method to a Swedish and a German population of Arabidopsis thaliana demonstrating a selfing rate of ca. 0:87 and the absence of any detectable seed-bank. In contrast, we show that the water flea Daphnia pulex exhibits a long lived egg-bank of three to 18 generations. Second, I will provide recommendations for the use of SMC-based methods for non-model organisms, highlighting the importance of the per site and the effective ratios of recombination over mutation. Third, I will show some preliminary results on the effect and estimation of a violation of the Wright-Fisher model assumption, namely the large variance in offspring production which is common to fish, invertebrates and fungal species. Finally, if time permits, I will show some preliminary results on the use of methylation patterns to enhance the power of inference under an SMC model using both genetic and epigenetic markers.