DFG FOR 1078 Natural Selection in Structured Populations

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Seminars 2011

10/01/11 - Prof. Asger Hobolth - "Estimating Ancestral Population Parameters"

Department of Mathematical Sciences, Aarhus University, Denmark

hobolthAbstract: For closely related species, the evolutionary history of an individual gene need not reflect the history of species divergences. Partly because of gene tree discordance, phylogenies of species reconstructed from different parts of a genome may suggest different relationships among the various species. We are developing theory that takes gene tree discordance into account, and we use the phenomenon to estimate population genetic parameters for closely related species. I will broadly discuss the methodology that we use for analysing various types of population genetic data sets.

17/01/11 - Dr. Floyd Reed - "Underdominance Predictions and Population Transformations"

Max-Planck Institute for Evolutionary Biology, Ploen, Germany

reedAbstract: Interest has been rapidly increasing in recent years in using genetic systems to manage wild insect populations. This ranges from population suppression using sterile insect technique to genetically transforming a population with desirable alleles using "selfish" genetic systems. However, many of these population transformation approaches are not predicted to be spatially contained or reversible (able to be completely removed from the wild). Underdominace is an "old" idea that we are revisiting as a method to transform populations with desirable alleles in a safe and reversible fashion. Underdominant constructs, under certain conditions, are not predicted to spread far from population to population by migration, and conditions exist where these genetic modifications can be completely removed from the wild by natural selection.

24/01/11 - Prof. Henrik Kaessmann - "Comparative RNA sequencing reveals the evolution of gene expression in mammalian organs"

Center for Integrative Genomics, University of Lausanne, Switzerland

kaessmannAbstract: Evolutionary changes in gene regulation have long been thought to underlie most phenotypic differences between species. However, evolutionary analyses of gene expression variation were long hampered by the limitations of microarrays for between-species comparisons. The recent development of RNA sequencing now affords essentially unbiased transcriptome comparisons at unprecedented resolution. We have generated detailed qualitative and quantitative transcriptome data using next generation sequencing technologies for a unique collection of germline and somatic tissues from representatives of all major mammalian lineages: placental mammals (humans, apes, monkeys, rodents), marsupials (gray short-tailed opossum), and the egg–laying monotremes (platypus). Our comparative and evolutionary analyses of these unprecedented data provide detailed insights into patterns of gene expression change in mammals and the underlying evolutionary forces. The data also allow us to explore, for the first time, the relevance of observed gene expression changes for the evolution of mammalian phenotypes.top

31/01/11 - Prof. Janis Antonovics - "Evolution of host-pathogen genetic systems: from plants to humans"

Department of Biology, University of Virginia, USA

antonovicsAbstract: Genetic variation in host resistance to pathogens is sometimes essentially absent, whereas at other times it exhibits complex, Rococco-like, genetics. We don't know why. I will present our recent studies addressing this question, namely, (a) evolution of genetic specificity in the flax-rust gene-for-gene system, (b) co-evolution between resistance pathways that are independent at the molecular level, and (c) a comparative study of human genetic variation in resistance to different infectious diseases.

09/05/11 - Dr. David Kirby - "Lab Coats in Hollywood: Scientists’ Backstage Role in the Production of Popular Films"

Centre for the History of Science, Technology and Medicine, University of Manchester

kirbyAbstract: Most people are unaware of scientists’ significant influence on the content of popular films. Yet, films ranging from A Beautiful Mind and Contact to Finding Nemo and Hulk have achieved some degree of scientific credibility because of science consultants. In this talk I elaborate on the backstage role scientific experts play in negotiating information transfer between the scientific community and the entertainment community in the production of popular films. Drawing on interviews and archival material, I will examine such science consulting tasks as fact checking, shaping visual iconography, advising actors, enhancing plausibility, creating dramatic situations, and placing science in its cultural contexts. I will also show how cinema can influence science as well by promoting research agendas, stimulating technological development, contributing to scientific controversies, and stirring citizens into political action.

23/05/11 - Dr. Claudia Fricke - "Costs and benefits of mating in Drosophila melanogaster"

University of East Anglia"

frickeAbstract:Sexual selection is an important selective agent and shapes not only sexual ornaments but also traits related to individual fitness. Sexual selection has traditionally been viewed as a harmonious cooperation between the sexes to ensure successful reproduction, whereby females choose between males and males compete against each other for mating opportunities. Recently though, this view has been challenged as new theory shifted our attention to the possibility of conflict occurring between the sexes. Sexual conflict occurs when the evolutionary interests of males and females differ, resulting in opposing selection pressures over shared traits like mating rate. In my research I use the fruit fly Drosophila melanogaster and ask whether sexual selection or sexual conflict have shaped reproductive traits of interest. D. melanogaster males transfer over 120 different proteins in their ejaculate at mating. The full complement of these seminal proteins is known to shorten female lifespan and result in significant fitness costs to females. Our work utilises molecular and behavioural tools to investigate whether reproductive proteins and here particularly the sex peptide are mediating sexual conflict between the sexes. Furthermore I present data on biotic and abiotic factors that have the potential to alter the outcome of male-female interactions to highlight the dynamic nature of the selection pressures shaping male and female reproductive traits.top

25/07/11 - Prof. Marco Thines - "Unravelling the functional genetics of host jumps in oomycetes and their evolutionary implications"

Biodiversity and Climate Research Centre, University of Frankfurt

thinesAbstract: Oomycetes are a group of fungal-like eukaryotes which share their evolutionary roots with brown algae and diatoms. With more than 1000 currently-known species, the highly host specific downy mildews are the largest group of these organisms. Within the downy mildews, several host jumps can be observed, which are often followed by radiation events. Downy mildews, like other plant pathogens, manipulate their hosts with a suit of effector proteins, which enable the pathogens to colonise their hosts. Especially cytoplasmic effectors, which suppress plant defence pathways, play a crucial role in this process. So far, nothing is known about the impact of host shifts on the effector complement of plant pathogens, despite their importance for understanding pathogen diversity and evolution . Recently, we established species of the Hyaloperonospora arabidopsidis cluster as model system to investigate this matter. The results obtained so far show a complex pattern of adaptation with divergent evolutionary forces exerted on specific effectors. While some effectors got lost, others underwent drastic gene duplication and paralogisation. Many effectors show strong signatures of positive selection at specific domains, indicative of the adaptation to the new effector targets encountered during a host shift, which enabled efficient colonisation of the new host.

31/10/11 - Dr. Kayla C. King - "Sex, promiscuity, and the Red Queen: interactions between a freshwater snail and its parasites"

Evolution, Ecology and Behaviour, University of Liverpool

kingAbstract: The maintenance of sex in natural populations is a pressing question for evolutionary biologists. Under the Red Queen Hypothesis, coevolving parasites reduce the reproductive advantage of asexual reproduction by adapting to common clonal genotypes. Genetically diverse offspring produced by sexual females are more difficult targets for coevolving parasites. I will present results indicating that sex in a New Zealand freshwater snail (Potamopyrgus antipodarum) is associated with coevolutionary hotspots for virulent parasites in natural populations. In addition, I will show that exposure to parasites boosts snail sexual activity and promiscuity, which may increase reproductive assurance in the face of virulent infection.

21/11/11 - Prof. Ted Morrow - "Two sexes, one genome: transcriptional studies of sexual antagonism in flies"

Evolutionary Biology Center, Uppsala University

morrowAbstract: Males and females of many species are thought to experience unique selection pressures throughout their reproductive lives. As a consequence, the genetic code from which the phenotype arises may be doomed to failure since no single solution will satisfy the requirements of selection, which differs between the sexes. An important issue for evolutionary biologists therefore is to determine the identity and nature of genetic loci that evolve under this form of sexually antagonistic selection. Here I will describe a series of experiments that were designed to examine sex-specific effects on gene expression in the fruit-fly with the aim of learning more about how sexual conflict influences the genome and the whole organism.

28/11/11 - Dr. Jarek Bryk - "On the functional analyses of putatively adaptive traits"

Department for Evolutionary Genetics, Max-Planck Institute for Evolutionary Biology, Plön

brykAbstract: Availability of genomic sequences and possibility of analysing whole-genome variation in many genomes of humans and their close evolutionary relatives allowed for identifying differences between our genome and theirs. However, they are many, and if one wants to learn “what makes us human” (on the molecular level at least) the key task is to identify those that contribute to functional differences between the species. This challenge is obviously not limited to great apes: any population–genetic or bioinformatic evidence for natural selection acting on some genomic sequence ought to be followed up with a functional study on its effects on the organism. I will present an overview of our attempts to use in vitro and animal models to elucidate function of genes that might have contributed to the evolution of some human phenotypes.