EES seminars 0809
From EESwiki
Seminars take place on Mondays at 17:00h in the Biozentrum, first floor, left lecture hall.
04/05/09 Prof Dr Ilona Kadow
Max Planck Institute for Neurobiology Martinsried, Germany
website: http://www.neuro.mpg.de/english/people/kadow_i.shtml
Title: Micro-RNA 279: a single gene as a regulator of olfactory system spefication
Abstract: Carbon dioxide (CO2) elicits different olfactory behaviors across species. In Drosophila, neurons that detect CO2 are located in the antenna, form connections in a ventral glomerulus in the antennal lobe, and mediate avoidance. By contrast, in the mosquito these neurons are in the maxillary palps (MPs), connect to medial sites, and promote attraction. We found in Drosophila that loss of a microRNA, miR-279, leads to formation of CO2 neurons in the MPs. miR-279 acts through down-regulation of the transcription factor Nerfin-1. The ectopic neurons are hybrid cells. They express CO2 receptors and form connections characteristic of CO2 neurons, while exhibiting wiring and receptor characteristics of MP olfactory receptor neurons (ORNs). We propose that this hybrid ORN reveals a cellular intermediate in the evolution of species-specific behaviors elicited by CO2.
Contact person: Ricardo Wilches
11/05/09 Prof Dr Gregor Bucher
Georg-August-Universität Göttingen - Developmental Genetics
website: http://wwwuser.gwdg.de/~gbucher1/
Contact person: John Baines
18/05/09 Prof Dr John Kelly
University of Kansas - Dept. of Ecology and Evolutionary Biology
website: http://www2.ku.edu/~eeb/faculty/kellyj.shtml
Title: The maintenance of genetic variation in quantitative traits: Results from the yellow monkeyflower
Abstract: A balance of evolutionary forces--mutation, selection, drift, and gene
flow--maintains quantitative trait variation within populations. For a
variety of questions, it is essential to understand whether natural
selection is mainly purifying (acts to eliminate variation) or balancing
(acts to maintain polymorphisms). Our group uses a combination of
genomic and biometric techniques to investigate quantitative trait
variation in the yellow monkeyflower, Mimulus guttatus. Thus far, the
accumation of evidence from a variety of experiments indicates that
natural selection likely maintains a large fraction of the standing
genetic variation in floral morphology, development rate, and male
fitness components.
Contact person: Laura Rose
25/05/09 Prof Dr Andrea Betancourt
University of Edinburgh
Title: "Recombination and adaptation in the Drosophila genome".
Abstract: In anisogamous organisms, sex carries a cost: every sexually reproducing female must produce two offspring to maintain a stable population size, while asexual females only need to produce one (Maynard Smith, 1978). In spite of this cost, sexual reproduction is widespread. * *One possible explanation is that recombination is advantageous, as it allows selection to act on alleles independently. If so, the advantage of recombination may be evident within genomes, by contrasting regions with different levels of recombination. I will discuss patterns of protein polymorphism and divergence in high vs. low recombination regions of the /Drosophila /genome. These patterns reveal that both purifying and positive selection are impaired in low recombination regions.
Contact person: John Baines
02/06/09 *TUESDAY* Prof Dr Peter Linder
University of Zurich, Department of Systematic Botany and the Botanical Garden
website: http://www.systbot.uzh.ch/institut/personen/person.php?l=e&id=23
Title: Adaptive radiation, lineage diversification and niche expansion: how can a great species richness be packed into a small area?
Abstract: A puzzling phenomenon is the occurrence of large numbers of closely related, endemic, species in a relatively small area (eg Erica in the Cape flora of South Africa, Lupinus in the Andean alpine regions, Veronica in New Zealand). Somehow these species are "packed" into the available niche space. I use an almost complete species phylogeny of the 300 species of African Restionaceae, and a comprehensive ecological dataset, to explore the patterns of species packing in these wind-pollinated plants in the Cape flora. Contrary to expectations, niche conservatism is more common than niche hyper-dispersal. Nonetheless, niche shifts can account for much of the co-existence of closely related species.
Contact person: Pablo Duchen and Delsy Trujillio
15/06/09 Prof Dr Eörs Szathmary **CANCELLED** Dr. Long will speak this day, see below
Collegium Budapest - Department of Plant Taxonomy and Ecology
website: http://www.colbud.hu/fellows/szathmary.shtml
Contact person: John Baines
15/06/09 Prof Dr Tony Long *at 17:00*
University of California at Irvine: Department of Ecology and Evolutionary Biology
website: http://cstern.bio.uci.edu/
Contact person: Laura Rose
Abstract: In the nineties it was widely believed that many Quantitative Trait Loci (QTL) could be positionally cloned in much that same manner as Medelian disease loci. Things did not really pan out. Early in this decade it was widely believed that Genome-wide Association Studies (GWAs) would save the day. Now that several human GWAs are complete there is much less certainty. Typical high powered studies are only able to account for a small percentage of standing genetic variation. What to do next? A new approach gaining ground employs "synthetic" populations to dissect complex traits. We are behind one such synthetic population resource in Drosophila. We will discuss some of the features of such populations, and why we think they may give us some leverage other methods have lacked.
29/06/09 Prof Dr Jan-Peter Frahm
Rheinische Friedrich-Wilhelms-Universität Bonn, Nees-Institut für Biodiversität der Pflanzen
website: http://www.bryologie.uni-bonn.de/deutsch/frame.htm
Title: Ammonia – the overlooked pollutant
Abstract: Although the emissions of NO2 are slightly but steadily decreasing over the past years, the nitrophilous species amongst epiphytic lichens and bryophytes are much increasing during the same time. Our studies revealed that the amount of NO2 measured at the control stations in Northrhine Westphalia does not correlate with the number and frequency of nitrophytic lichens. Therefore NO2 cannot be responsible for the nitrogen effects. Fertilizer experiments show on the other hand, that fertilizer containing ammonia have significantly higher effects on lichens than those based on nitrate. In the city of Düsseldorf, the occurrence of nitrophytic lichens correlates with the amount of ammonia in the air. Source of ammonia in cities are emissions of catalysts (!), on the countryside emissions of the agriculture. Ammonia, however, reacts with NO2 in the air forming ammoniumnitrate. This is a (purchasable) super fertilizer. Furthermore, ammoniumnitrate is dry deposition and forms particulate matter (PM1). About half of particulate matter consists of ammoniumnitrate. An analysis of amino acids in lichens shows that nitrogen is not metabolized but deposited as amino acids. The higher the nitrogen load of the region the higher is the contents of amino acids, since lichens are passive sampler which cannot control the uptake of nitrogen. Therefore so called nitrophilous lichens are in fact only nitrogen tolerant. Since ammoniumnitrate is a salt and applied as dry deposition, these lichens must be salt tolerant and have higher osmotic values, which could be proved. Thus the problem of eutrophication by nitrogen emissions is basically a salt problem for the plants. This is shown by the increase of salt plants along highways, which are favoured by ammoniumnitrate produced by catalysts (ammonia) and diesel cars (NO2) and not from dredging with lowered amounts of KCl.
Contact person: Rob Morrison and Jennifer Lohr
06/07/09 Prof Dr Mark Beaumont
University of Reading, UK
website: http://www.rubic.rdg.ac.uk/~mab/
Title: Likelihood-free inference of local selection
Abstract: Approximate Bayesian computation (ABC) has proved useful for complex models in which the likelihood function is difficult or expensive to obtain. This approach typically requires the data to be compressed into summary statistics. In a hierarchical setting one may be interested both in hyper-parameters and parameters, and there may be very many of the latter - for example, in a genetic model, these may be parameters describing each of many loci or populations. This poses problems for ABC in that one then requires summary statistics for each locus and/or population with concomitant problems of scaling. We develop a general method for addressing these problems efficiently, and we describe recent work in which the ABC method can be used to detect loci under local selection. Authorship: Eric Bazin (CIRAD, Montpellier), Kevin Dawson (Rothamsted Research), Mark Beaumont (University of Reading)
Contact person: Dirk Metzler
13/07/09 Prof Dr Ido Pen
University of Groningen - Department of Theoretical Biology
Website: http://www.rug.nl/biologie/onderzoek/onderzoekgroepen/theoreticalbiology/peoplePages/idoPage
Title: Evolution of maternal effects under conflicts, costs and constraints
Abstract: The evolution of maternal effects on offspring phenotype should depend on the extent of parent-offspring conflict, constraints on information processing and costs of maternal and offspring strategies. Yet, there has been little formal theory of how each of these modulates the strength and direction of maternal effects and the implications for their adaptive significance. Here we construct a meta-population model of natal dispersal that allow inclusion of different degrees of conflict, costs of maternal and offspring strategies and constraints on information acquisition and counter responses to strategies by the other party. Our results show that maternal effects on offspring dispersal rates from different environments will reflect the offspring optima in the absence of costs or constraints. This result also holds true when offspring do not have access to information about their own environment. However, constraints on counter responses can lead to maternal effects at the maternal optima. Furthermore, maternal effects involving costly strategies can evolve to correspond with those under complete maternal or offspring control, depending on who incurs the cost and its magnitude. Our model provides support for verbal arguments for the importance of conflicts, cost and constraint in the evolution of maternal effects and shows how an understanding of the underlying mechanisms is crucial to generate directional predictions with respect to evolutionary responses to selection. We use our results to reinterpret some recent work on maternal effects and provide suggestions for future work.
Contact person = Ricardo Wilches and Rebecca Meredith
20/07/09 Prof Dr Alistair McGregor
University of Veterinary Medicine Vienna, Institute for Population Genetics
website: http://i122server.vu-wien.ac.at/pop/McGregor_website/mcgregor_home.html
Title: Investigating the genetic basis of morphological variation within and between Drosophila species
Abstract: In the last 10 years there has been much progress in understanding the genetic basis of morphological variation among species. However, there are three areas that need to be further addressed to test current models and give a more complete picture of morphological evolution: What is the genetic basis of differences in quantitative traits such as organ shape and size? What evolutionary forces have shaped morphological differences? To what extent does standing genetic variation contribute to differences between species? I will discuss ongoing projects in my lab investigating the evolution of eye size and trichome patterns within and among Drosophila species that aim to address these questions.
Contact person: John Parsch
See older seminar series at EES Seminar Series 2008/2009
