20201-2022 Seminar Series

Full List 2021-2022

2021-2022 Schedule


April 8, 2022

Dr. Banu Subramaniam, University of Massachusetts Amherst
Decolonizing Botany  POSTER RECORDING

What does it mean to be a feminist botanist?  Drawing on recent interdisciplinary scholarship, I show how gender, race, class, sexuality, and nation shape the foundational language, terminology, and theories of modern botany, and how botany remains grounded in the violence of its colonial pasts. Decolonizing Botany reckons with these difficult origins and lays a roadmap to imagine a renewed botany that bring scholarship from the humanities and the sciences to reimagine the practices of experimental biology.

April 1, 2022

Seema Sheth, North Carolina State University

The role of demographic and evolutionary processes in buffering populations from climate change  POSTER RECORDING

Adaptive evolution is a key means for populations to persist under environmental change. Yet, whether populations can adapt quickly enough to keep up with the rapid pace of changing climate remains largely unknown. Further, range limit theory suggests that the probability of evolutionary rescue varies across species’ ranges. I will discuss previous and ongoing research examining the potential for demographic and evolutionary processes to buffer populations across a species’ range from climate change. This work, which uses western North American monkeyflowers as a model system, points to the need for field tests of evolutionary rescue that integrate quantitative genetics and population ecology.


Mar 25, 2022
Dr. Patrick Lynch, Yale University
Digital Field Guides to an Analog World POSTER RECORDING
I've had a life-long interest in both visual communication and various aspects of natural history, and was lucky enough to be able to combine my interests over a 45 year multimedia career at Yale University. This talk will look at the logistics of creating my books, all of which were wholly or at least partially generated with digital tools.
Host: Dr. Michael Corrin


Mar 18, 2022

Dr. Albert Porcar-Castell, University of Helsinki
Chlorophyll a fluorescence illuminates a path connecting plant molecular biology to Earth-system science



For decades, the dynamic nature of chlorophyll a fluorescence (ChlaF) has provided insight into the biophysics and ecophysiology of the light reactions of photosynthesis from the subcellular to leaf scales. Recent advances in remote sensing methods enable detection of ChlaF induced by sunlight across a range of larger scales, from using instruments mounted on towers above plant canopies to Earth-orbiting satellites. This signal is referred to as solar-induced fluorescence (SIF) and its application promises to overcome spatial constraints on studies of photosynthesis, opening new research directions and opportunities in ecology, ecophysiology, biogeochemistry, agriculture and forestry. However, to unleash the full potential of SIF, intensive cross-disciplinary work is required to harmonize these new advances with the rich history of biophysical and ecophysiological studies of ChlaF, fostering the development of next-generation plant physiological and Earth-system models. Here, we introduce the scale-dependent link between SIF and photosynthesis, with an emphasis on seven remaining scientific challenges, and present a roadmap to facilitate future collaborative research towards new applications of SIF.

Host: Dr. Ingo Ensminger


Mar 11, 2022

Dr. Julie Lefebvre, Senior Scientist, Program for Neuroscience & Mental Health, Hospital for Sick Children Research Institute
Assistant Professor of Molecular Genetics, University of Toronto

Molecular strategies for wiring inhibitory neurons into circuits
Host: Dr. Baohua Liu


In the developing nervous system, an enormous number and diversity of neurons are precisely organized into neural circuits.  How can such a vast set of neural connections be wired using limited cues encoded in our genomes? To tackle this problem, we are studying a family of neuronal receptors with an extraordinary potential for conferring cell-surface diversity and wiring specificity in the developing mouse brain and retina. The clustered Protocadherin genes (cPcdhs) are tandemly arrayed on a single genomic locus and encode ~60 cadherin-related transmembrane proteins that are combinatorially expressed among single neurons. We propose that the cPcdhs serve as a code for ‘neuron individuality’ to mediate complex patterns of connectivity. I will discuss our work on the multiple roles of the cPcdhs for regulating the survival and integration of GABAergic inhibitory interneurons, as well as for dendrite self-avoidance during circuit formation. These studies will yield new insights on the cell-cell interactions and molecular cues that establish the proper balance and wiring of inhibitory cells into circuits.   


Mar 4, 2022

Dr. Jacqueline Sztepanacz, Department of Ecology and Evolutionary Biology, University of Toronto

Evolvability in the face of pleiotropy: linking micro- and macro- evolution  POSTER RECORDING

Host: Dr. Rob Ness



Stabilizing selection holds a central role in evolutionary theory and has been invoked as the key process determining macroevolutionary patterns of trait evolution. However, studies that measure selection in contemporary populations often find that diversifying mechanisms of selection are stronger and more prevalent. How to resolve this paradox of stasis is not clear, despite a great deal of effort. An underappreciated aspect of stabilizing selection is that most of it will not act on individual traits, but arises from the pleiotropic effects of alleles that underlie a focal trait and many other unknown or unmeasured traits that affect fitness. Understanding the interaction between genetic variation, stabilizing selection and the pleiotropic relationships among traits is, therefore, critical to uncovering how stabilizing selection influences trait evolution on both micro- and macro- evolutionary timescales. In this talk I will share my work on how genetic variation is distributed across multivariate trait combinations, how sexually antagonistic pleiotropy affects the evolvability of populations, and how strong apparent stabilizing selection is in contemporary populations.


Feb 18, 2022

Dr. Nic Kooyers, University of Louisiana, Lafayette

The double-edged sword of rapid adaptation: facilitating invasions or responses to climate change? POSTER RECORDING

Host: Dr. Marc Johnson


The ability of selection to act on ecologically relevant timescales has become increasing apparent during the Anthropocene. Rapid adaptation can be beneficial to conservation interests when populations are able to quickly adapt in response to changing climates, but can be destructive when introduced species evolve to become more invasive. Here we explore these divergent roles for adaptation in the context of a native North American species of wildflower, Mimulus guttatus, that faces substantial climatic changes to its subalpine habitat as well as for a perennial herb, Trifolium repens, that has been introduced across the world from its native Eurasian range. To assess the role of adaptation in climate change, we first examine whether M. guttatus populations are locally adapted to their current conditions at their home sites or whether populations exhibit maladaptation because they are better adapted to historic conditions at their home site – a pattern termed adaptation lag. We investigate the climatic factors driving potential adaptation lags and whether future adaptation is constrained by lack of phenotypic variation or genetic tradeoffs between traits. To determine the role of adaptation in invasions, we assess how patterns of genetic and phenotypic variation differ across continent-wide ecological gradients in the native and introduced ranges and use common garden experiments to examine patterns of local adaptation. We use these data to examine the tempo and mode of adaptation as well as to test whether convergent evolution occurs across independent introduction events. While our results suggest that rapid adaptation impacts each of these species, they also suggest that adaptation is limited by the genetic architecture of ecological important traits and the variation present within the target populations.


Feb 11, 2022

Dr. Valeria Lencioni, MUSE - Museo delle Scienze di Trento

Evidences of global warming effects on macroinvertebrate communities in Alpine glacier-fed streams  POSTER RECORDING

Freshwater biodiversity is increasingly endangered by the consequences of climate change, environmental pollution, habitat fragmentation or flow regulation, and invasive species. In mountain regions, increased temperatures are resulting in glacial retreat globally. Glacial retreat is leading to cascade effects on glacier-fed streams, from altered hydrological, thermal, and biogeochemical cycles to quarter quality depletion and biodiversity loss. Specifically, how do macroinvertebrate communities respond to declining glacial influence? What will be the fate of the cold stenotherm species most specialised in living in the cold? Starting from their ecological valency investigated at physiological, biochemical and genetic level, evidences of climate change and pollution effects on glacial biodiversity will be presented from case studies in the Italian Alps.
Web links:
Scientific Coordinator of Climate & Ecology Area, Research and Museum Collections Office, MUSE-Museo delle Scienze/Science Museum of Trento, Italy
I am an hydrobiologist, grew up in a mountain village in the Brenta Dolomites, in the Italian Alps, recognized as a UNESCO World Heritage Site. Fascinated by extremely cold habitats, I am studying the ecology of headwaters (springs, lakes and streams) in glaciated areas, satisfying in this way also my curiosity of nature and passion for mountains, aquatic habitats and insects. At present the main focus is on the effects of climate change on glacial habitats and biodiversity, evaluated with an holistic approach, from gene to ecosystems. Specifically, I have devoted most of my research on taxonomy, autecology, physiology, and genetic adaptation of chironomids (Diptera Chironomidae), the most frequent and abundant animal taxon living in glacier-fed streams, today threatened by extinction by climate change and pollution. I have two decades of experience in coordinating work packages or projects within national and international frameworks, menthoring PhDs and master students, writing scientific papers (79-ISI papers in WOS and Scopus databases) and organisation of public events (from international congresses to project meetings and events for non-experts and non-academic stakeholders).


Feb 4, 2022   CANCELED
Dr. Douglas Allan, The University of British Columbia
Transcriptional control of synaptic functional maturation
Host: Dr. Ted Erclik


Jan 28, 2022

Dr. Carolyn Wessinger, University of South Carolina

Evolutionary genetics of parallel floral evolution in penstemon wildflowers



The wildflower genus Penstemon displays a remarkable pattern of parallel floral evolution, where flowers adapted to hummingbird pollinators have repeatedly evolved from ancestral bee pollination. I will discuss recent macroevolutionary modeling that suggests transitions from bee to hummingbird pollination in this genus occur more frequently than transitions in the reverse direction, and that hummingbird-pollinated lineages show reduced speciation rates. An untested hypothesis is that pollination by hummingbirds results in greater connectivity among populations, reducing the opportunity for allopatric speciation. The transitions from bee to hummingbird pollination in Penstemon have likely occurred recently, since hummingbird-pollinated species in Penstemon are nearly always sister to bee-pollinated species. I will discuss population genomic and quantitative genetic work in a focal sister species pair that suggests adaptive floral divergence involves relatively few genetic changes of major effects that maintain complex floral divergence, despite substantial shared genetic variation between sister species.

Host: Prof. Helene Wagner


Jan 21, 2022

Dr. Alonso Ramirez, North Carolina State

Urbanization and stream ecosystems in Puerto Rico: Biotic responses to major disturbances



Urbanization is a major source of stress to stream ecosystems resulting in communities dominated by non-native species. In Puerto Rico, urban streams have high levels of pollutants, altered geomorphology, and most of the expected urban symptoms. However, they continue to maintain native biotic assemblages. In this seminar, I explore biotic responses to urban and non-urban disturbances and potential mechanisms by which native species are able to cope with urban impacts. Our focal watershed drains the San Juan metropolitan area, the most urbanized region in Puerto Rico.

Host: Dr. Shannon McCauley

Jan 14, 2022


Maliha Islam, PhD Student, Ted Erclik Lab
Concurrent temporal patterning of stem cells in the developing fruit fly brain

The Drosophila medulla, which is the largest neuropil in the optic lobe, is as an excellent model system in which to study the mechanisms that regulate neurogenesis. Its 40,000 neurons, which comprise over 90 cell types, are generated from a neuroepithelial crescent termed the outer proliferation center (OPC). Beginning at the onset of the third larval instar, and continuing for two days, a proneural wave converts each neuroepithelial cell into a neuroblast (NB), which subsequently divides asymmetrically to generate two neurons via an intermediate ganglion mother cell. It has previously been shown that two axes of positional information act on OPC NBs to generate neural diversity. In the temporal axis, a cascade of five genes--Homothorax, Eyeless, Sloppy paired, Dichaete and Tailless--are sequentially expressed in each of the medulla NBs as they age. In the spatial axis, the OPC crescent from which the NBs are generated is sub-divided into eight compartments (patterned by four genes: Vsx1, Optix, Rx, and Hh). Distinct neuronal types are generated by NBs based on their spatio-temporal address. Here, we describe a third patterning axis that further diversifies neuronal fates in the medulla. We show that the neuroepithelium from which the NBs are generated is itself temporally patterned by the sequential expression of five genes over the two-day period of neurogenesis. The temporal patterning of the neuroepithelium confers NBs from the same spatio-temporal address with unique identities based on the time that they are generated. Using clonal, EdU-birthdating and functional analyses, we show that NBs in the Vsx1-Hth spatio-temporal window generate not one, but five, distinct neuronal types over the course of neurogenesis. We further demonstrate that long-range temporal patterning extends beyond the Vsx1-Hth NB window and functions as a mechanism to couple neurogenesis with medulla circuit assembly.


Wassim Elkhatib, PhD Student, Adriano Senatore Lab

The evolutionary emergence of acid-sensing ion channels in Trichoplax adhaerens, an animal without a nervous system

The degenerin/epithelial sodium channel (DEG/ENaC) superfamily emerged in the oldest animals on earth and have undergone extensive lineage specific evolution leading to very diverse functional properties. All DEG/ENaCs share a common structure made up of three subunits, with each subunit consisting of two transmembrane helices and a large extracellular domain. In invertebrate lineages, DEG/ENaCs have evolved a response to various ligands and sensory inputs, such as the touch sensing MEC4/10 channels in nematodes, the pheromone sensing pickpocket 25 channel in fruit flies and the peptide gated FMRFamide-gated sodium channel (FaNaC) channels in molluscs (snails). Deuterostome (Chordates, Hemichordates, & Echinoderms) DEG/ENaCs diverged into two functionally distinct groups; 1) ENaCs, which are constitutively open Na+ channels that regulate sodium reabsorption and blood pressure in the kidneys, 2) acid-sensing ion channels (ASICs) which fully activate in acidic environments, found in the central and peripheral nervous system, and play major roles in memory, stroke detection and pain sensation. Clearly, DEG/ENaC expansions across animal lineages is complex and until all major phyla are studied, their core properties and physiological functions will remain unknown. My lab studies Trichoplax adhaerens an early-diverging marine animal that has no synapses or muscles, yet conducts motile behaviours mediated by peptides. Using our Trichoplax transcriptome, we identified and cloned nine DEG/ENaC homologs dubbed Trichoplax adhaerens sodium channels 2-10 (TadNaC2-10). We functionally expressed TadNaC6 in Chinese hamster ovary cells (CHO-K1) and used in-vitro patch-camp electrophysiology to show that TadNaC6 is inhibited by extracellular acid and calcium, but activated by amiloride, a robust blocker of DEG/ENaCs. Our current work is revealing that TadNaC2 also forms functional channels that unexpectedly show great resemblance to deuterostome ASICs, although they lack many of the fundamental amino acids involved in deuterostome ASIC gating. Our work suggests the independent evolution of ASIC channels in Trichoplax adhaerens and the uncovering of DEG/ENaCs across all animal lineages and certain prokaryotic organisms.


December 10, 2021
Dr. Pierre Legendre, Universite de Montreal POSTER
Temporal beta diversity: identify sites where species communities have changed in exceptional ways
Aim This paper presents the statistical bases for temporal beta diversity analysis, a method to study the changes in community composition through time from repeated surveys at several sites. Surveys of that type are presently done by ecologists around the world. A Temporal Beta-diversity Index (TBI) is computed for each site, measuring the change in species composition between the first (T1) and second surveys (T2). TBI indices can be decomposed into losses and gains; they can also be tested for significance, allowing one to identify the sites that have changed in composition in exceptional ways. This method will be of value to identify exceptional sites in space-time surveys carried out to study anthropogenic impacts, including climate change.
Innovation The null hypothesis of the TBI test is that a species assemblage is not exceptionally different between T1 and T2, compared to assemblages that could have been observed at this site at T1 and T2 under H0. Tests of significance of coefficients in a dissimilarity matrix are usually not possible because the values in the matrix are interrelated. Here, however, the dissimilarity between T1 and T2 for a site is computed with different data from the dissimilarities used for the T1–T2 comparison at other sites. It is thus possible to compute a valid test of significance in that case. In addition, the paper shows how TBI dissimilarities can be decomposed into loss and gain components (of species, or abundances-per-species) and how a B-C plot can be produced from these components, which informs users about the processes of biodiversity losses and gains through time found in space-time survey data.
Applications An application of the method to the Barro Colorado Forest Dynamics plot (BCI, Panama) will be presented in detail, comparing the 1985 and 2015 surveys. Applications of the method to other ecological communities will be mentioned, including a study of paleo-ecological data. This method is applicable worldwide to all types of communities, marine and terrestrial. R software is available implementing the method.
Brice, M.-H., K. Cazelles, P. Legendre & M.-J. Fortin. 2019. Disturbances amplify tree community responses to climate change in the temperate-boreal ecotone. Global Ecology & Biogeography 28:1668–1681.
Kuczynski, L., P. Legendre & G. Grenouillet. 2018. Concomitant impacts of climate change, fragmentation and non-native species have led to reorganization of fish communities since the 1980s. Global Ecology and Biogeography 17: 213–222.
Legendre, P. 2019. A temporal beta-diversity index to identify sites that have changed in exceptional ways in space-time surveys. Ecology and Evolution 9: 3500–3514. https://doi.org/10.1002/ece3.498
Legendre, P. & R. Condit. 2019. Spatial and temporal analysis of beta diversity in the Barro Colorado Island forest dynamics plot, Panama. Forest Ecosystems 6: 1–11.  https://doi.org/10.1186/s40663-019-0164-4
Legendre, P., & B. Salvat. 2015. Thirty-year recovery of mollusc communities after nuclear experimentations on Fangataufa atoll (Tuamotu, French Polynesia). Proceedings of the Royal Society B 282: 20150750.
Winegardner, A. K., P. Legendre, B. E. Beisner & I. Gregory-Eaves. 2017. Diatom diversity patterns over the past ~ 150 years across the conterminous United States: identifying mechanisms behind beta diversity. Global Ecology and Biogeography 26: 1303–1315.
December 3, 2021
Dr. Katie Plaisance, University of Waterloo POSTER  RECORDING
The Science of Team Science: How to Foster Productive Collaboration in Interdisciplinary Science Teams
Interdisciplinary approaches to scientific research are on the rise. This is in part because many of the complex problems we face as a society – and the research questions scientists ask – cannot be addressed by one discipline alone. Universities and funding agencies are encouraging researchers to work across disciplinary boundaries and heavily incentivizing such approaches. However, the common barriers to interdisciplinary collaboration are not always well understood, especially amongst those engaging in such collaborations. In this talk, I will discuss some of the challenges that scientists (and other researchers) face when collaborating with others outside their field. Being aware of these challenges is a crucial first step in managing them. I then go on to discuss strategies for proactively addressing these challenges and highlight resources scientists can use to support their collaborative efforts.  
November 26, 2021
Dr. Marian Schubert, Norwegian University of Life Sciences
Evolution of temperate adaptations in grasses: Insights from molecular and macro-evolutionary studies POSTER. RECORDING
The grass family (Poaceae) is one of the largest and most successful plant families, both economically and ecologically. It contains staple crops such as wheat, rice, and maize and covers a wide geographic and climatic range. Grasses are diverse in areas that regularly experience cold and freezing as well as high seasonality. To meet the challenges of such environments, temperate grasses have evolved a rich arsenal of strategies to cope with stresses imposed by cold and short growing seasons. To better understand the molecular basis of these complex, adaptive mechanisms and how they evolved in the different grass lineages is the main aim of my research. I will sum up findings of different projects to show how we combine physiological, omic and phylogenetic comparative data to elucidate the evolutionary history of temperate adaptions in grasses.
November 19, 2021
Dr. Satoru Miura, University of California San Francisco
Why the world stands still when we move our eyes - Mechanistic insights from mouse visual
Sensory stimuli are often evoked by the animal’s own actions. In both vertebrates and invertebrates, nervous systems distinguish these self-generated stimuli from stimuli evoked by changes in the environment. How this distinction is achieved has been the subject of much investigation, especially in the context of saccades. Saccades are rapid eye movements performed by many animals across phyla, and they induce a quick motion of the visual scene on the retina. Behavioral studies show that this saccade-induced motion on the retina is distinguished by the subjects from motion that occurs in the environment. However, how the two types of motion are differentially processed by the visual systems is not fully understood. To address this issue, we recorded saccade responses in the primary visual cortex (V1) of awake mice and discovered that neurons in V1 are tuned to the direction of saccades, both in freely moving and head-fixed conditions. Given that many neurons in V1 are tuned to the direction of visual motion on the retina, could the directionally tuned saccade responses simply be visual responses? Contrary to this notion, we demonstrate that saccades and motion in the environment evoke distinct patterns of activity in V1, even when the resulting visual stimuli on the retina are identical. Indeed, for many directionally-tuned neurons, the preferred direction for motion in the environment differs from that for saccades. We show that this is because during saccades, neurons in V1 linearly integrate the visual input with a strong, non-visual input arriving from the pulvinar nucleus of the thalamus. This non-visual input can be observed under the complete lack of vision and encodes the direction of saccades. The input both precedes and outlasts saccades by tens of milliseconds, suggesting it may originate, at least partially, from the oculomotor command. Silencing the pulvinar prevented the non-visual input from reaching V1, such that the pattern of the evoked response in V1 was now similar regardless of whether the motion on the retina was generated by saccades or by changes in the environment. Thus, the pulvinar ensures differential responses in V1 to self-generated motion and external motion. The integration of sensory inputs with other inputs encoding postural states may be a general mechanism that allows the animal to interpret sensory information in the context of its own actions.
Host: Prof. Baohua Liu
November 12, 2021
Dr. Otso Ovaskainen, University of Helsinki
Joint species distribution modelling: how to make more out of community data? RECORDING
A central aim of community ecology is to understand the processes that determine the assembly and dynamics of species assemblages at different spatiotemporal scales. To facilitate the integration between conceptual and statistical approaches in community ecology, we have developed Hierarchical Modelling of Species Communities (HMSC) as a general, flexible framework for modern analysis of community data. HMSC belongs to the class of joint species distribution models, and it makes it possible to derive simultaneously species- and community level inference from data on species occurrences, environmental covariates, species traits, and phylogenetic relationships. HMSC applies to a wide variety of study designs, including hierarchical data, spatial data, temporal data, and spatio-temporal data. We describe the general HMSC framework and its relationships to other methods for analysing community data, demonstrate the R-package Hmsc by applying it to a case study on Finnish birds, and conclude by discussing the strengths and development needs of this methodological framework.
Host: Prof. Helene Wagner
November 5, 2021
Dr. David Baltrus, University of Arizona
Developing Phage Derived Bacteriocins as Strain Specific Antimicrobials
Since interactions between microbes can determine assembly dynamics within microbiomes, outcomes of these interactions have the potential to directly shape functional outputs of microbial communities. A deeper understanding of the molecules that drive these interactions may therefore enable fine scale manipulation of microbiomes in both clinical and agricultural settings. The Baltrus lab has previously characterized a suite of antimicrobial molecules (tailocins) produced by strains of Pseudomonas but derived from prophage, in which phage tails can be used as weapons to target and lyse specific closely related strains. We show that the host range of these molecules can be far wider than canonically thought but also that resistant mutations by some strains can actually sensitize these strains to killing by divergent tailocins (a phenomenon termed "collateral sensitivity"). Taken together, by understanding the molecular language of how amino acid divergence changes host range and by categorizing the genetic basis of collateral sensitivity, we hope to develop programmable antibiotics that can bind to and eliminate target cells while anticipating and countering resistance as it evolves.
Host: Dr. Marcus Dillon
October 29, 2021
Dr. Kari Segraves, Syracuse University
The evolutionary ecology of species interaction RECORDING
Species interactions play an important role in structuring communities and creating new species. Although these linkages have long been appreciated, understanding the myriad ways in which species interactions contribute to evolutionary change and, ultimately, diversification remain relatively unexplored. In this seminar, I will discuss two ongoing projects. First, I will address how the speciation process itself can affect the ecology of species interactions that span the mutualism-antagonism continuum. In the second half of the talk, I will present results on how the community context of multispecies mutualisms affects the ability of mutualists to ameliorate the negative effects of cheaters. Together, the results underscore the intertwined nature of species interactions, diversification, and community structure.
Dr. Kari Segraves received her Ph.D. from Vanderbilt University, and then was a NSF Interdisciplinary Informatics Postdoc at the University of Idaho before she moved to Syracuse University in 2005 where she is now a Professor of Biology. She is broadly interested in the role of species interactions in shaping biodiversity and uses a combination of field and laboratory experiments on model and non-model systems to test how species interactions influence the ecology and evolution of species and communities. She works with organisms across three kingdoms at both micro and macroevolutionary scales.
HOST: Prof. Marc Johnson
October 22, 2021
Dr. Matt Smear, University of Oregon
Neural correlates of time and place in the olfactory bulb of freely-moving mice RECORDING
Odors provide useful navigational and episodic information, but however numerous the odorant receptor genes in an animal’s genome, there is no receptor for time or place. To optimally orient by olfactory information, brains must incorporate odor-driven activity into representations of self-movement and -location. While a feedforward model might predict that such multimodal integration would be implemented in “high-level” areas, recent studies in other sensory modalities demonstrate that motor- and location-related signals are common in primary sensory areas. Motivated by these findings, and given the strong reciprocal connection between olfactory system and hippocampus, we hypothesized that the olfactory bulb might also encode navigational information. To test this hypothesis, we captured the sniffing and movement of mice while recording spiking activity in their olfactory bulb, in the absence of experimenter-applied stimuli or tasks. As previously reported, we found that many units fired preferentially at characteristic times after inhalation. In addition, many units fired preferentially at characteristic sniff frequencies, particularly during free movement, often in correspondence with the rhythmic states of sniffing. In addition to these time-selective signals, we also found that many olfactory bulb neurons are place-selective during free movement. To test whether this position-selective activity carries usable information about the mouse’s location, we decoded position from ensembles of simultaneously recorded units. We could decode the mouse’s position with above-chance accuracy in all sessions. Thus, even during spontaneous behavior and ambient stimuli, information about time and place can be read out from the activity of the olfactory bulb. A mouse needs to know where and when it encountered different smells: olfactory information must be contextualized and incorporated into cognitive maps of environment and self. Our results suggest that this contextualization process begins as soon as olfactory information enters the brain.
My research focuses on how neural mechanisms coordinate sensing with moving — how do animals sample the environment in order to acquire the information they require to survive? This broad question encompasses a snake flicking its tongue, a primate moving its eyes, or a rodent following its nose. I study the last of these because mice are particularly amenable for studying neural circuits. I am a neuroscientist, born in Saskatchewan, raised in Maryland. I attended Duke and UCSF for school and I did postdocs at Cold Spring Harbor and Janelia Farm. I have been at University of Oregon since 2014.
Host: Dr. Arbora Resulaj
October 8, 2021
Dr. Maitreya Dunham - Department of Genome Sciences at University of Washington
Taking yeast experimental evolution out of the lab and into classrooms and breweries. RECORDING
Host: Dr. Alex Nguyen Ba
Microbial experimental evolution has allowed for real time explorations of many important topics in evolution. Now paired with cheap and easy whole genome sequencing, we have been able to explore the genetics of adaptation at a level of molecular detail never before possible. I will talk about two projects where we've been able to apply the approaches and tools we developed to study evolution of yeast cultures in the lab, but now in classroom and industry settings. First, we have simplified our methods to allow high school students to perform experimental evolution as part of a teaching lab, with results contributing to a multi-school research project on how yeast evolve antifungal resistance. Second, we have taken advantage of a natural experiment happening in breweries, where yeast is "repitched" from one fermenter to the next. Using deep sequencing, we found chromosome rearrangements and copy number variants that repeatedly attained high frequency over yeast reuse, even across multiple breweries. We infer that these mutations are beneficial in the brewery environment and affect traits including osmolarity tolerance, flavor, and flocculation. We are hoping to build on these success stories to find new opportunities to study evolution in real time in non-lab environments.
Dr. Maitreya Dunham' research uses high-throughput experimental evolution to understand and exploit evolutionary processes in natural or biotechnological settings. She has set up chemostats to study laboratory and wild microbes in the lab, and exploits next-generation sequencing and advanced bioinformatics pipelines to decipher their genome evolution. She is extremely fun to talk to even for things outside the lab, for example she is involved in multiple breweries around Seattle as she brews her own and grows her own hops. For more information on her research and publications, visit her webpage (https://dunham.gs.washington.edu/home.shtml).
October 1, 2021
Dr. Cassidy D'Aloia, University of New Brunswick
Genetic approaches to uncovering marine connectivity RECORDING
Host: Dr. Bailey McMeans
Over 70% of marine species disperse as tiny larvae that develop in ocean currents. Determining where those larvae go—and how they get there—has been a major challenge in marine ecology. Genetic relatedness analyses that identify first-order kin, such as parents and their offspring or full siblings, have become a popular tool for documenting marine larval dispersal events. But these analyses come with their own drawbacks. Mainly, these studies are spatially and temporally constrained due to their sampling intensity, rendering them ill-suited for detecting long-distance dispersal and/or temporal fluctuations in connectivity patterns. In this talk, I’ll present recent work that integrates multiple genetic approaches to detecting larval dispersal across spatial and temporal scales. We assess the benefits and shortcomings of our own genetic relatedness studies. Collectively, we find evidence of consistently limited dispersal in a coral reef fish, despite the fact that individuals develop and feed offshore in pelagic waters for nearly a month. These results pave the way for new integrative lines of research that explore the behavioral and oceanographic mechanisms driving these dispersal patterns.
I am a molecular ecologist and marine field biologist who grew up in landlocked upstate NY. My interest in EEB and marine science was first sparked while studying as an undergraduate at Middlebury College and the Universidad Austral de Chile. After that, I spent five years (often underwater!) studying coral reef fishes in Belize during my PhD. I completed postdocs at Woods Hole Oceanographic Institution and the University of Toronto before moving to the University of New Brunswick as an Assistant Professor. In January 2022 I am joining the UTM Department of Biology.
Website: https://www.cassidydaloia.com/
September 24, 2021
Dr. Susan Gasser, Director of ISREC - Swiss Institute for Experimental Cancer Research
How heterochromatin preserves genome stability and tissue identity in worms. Recording
Development of an organism is governed by a carefully orchestrated program of gene regulation, controlled on the level of both chromatin and DNA sequence. Histone modifications are the primary drivers of chromatin structure, which shape the epigenetic information of any cell. Methylation of lysine 9 of histone H3 (H3K9me) characterizes the transcriptionally silent heterochromatin in organisms from yeast to man. It ensures genome stability by silencing repeats (1)  and it silences some genes as cells differentiate (2). In multicellular animals the aberrant gain or loss of heterochromatin and its segregation at the nuclear envelope has been correlated with a loss of tissue integrity, aging and cancer (e.g., 2,3,4).  Nonetheless, how H3K9me restricts expression remains unknown. Here we show in C. elegans that loss of H3K9me results in the limited depression of genes which in some tissues and/or embryos carry H3K9 methylation. We find that the pattern of gene derepression by loss of H3K9me is distinct in embryos and in terminally differentiated cells (5). During organismal development, we find that H3K9me is lost from genes that must be expressed, and is gained on genes that were expressed in prior developmental stages. Active H3K9me maintenance by MET-2/SETDB1 is necessary to ensure silencing, even in post mitotic cells. Despite the fact that H3K9me generally restricts chromatin accessibility at promoters and enhancers, as measured by ATAC-seq, we find that changes in accessibility do not necessarily correlate with gene derepression. Rather, the binding of a specific subset of TFs is controlled in differentiated tissues by H3K9me.  This substantiates the long-standing hypothesis that heterochromatin controls gene expression. Although derepression can be independent of stable chromatin opening, expression reflects the ability of TFs to access gene promoters (5).
  1. Zeller, P. et al. Histone H3K9 methylation is dispensable for Caenorhabditis elegans development but suppresses RNA:DNA hybrid-associated repeat instability. Nat Genet 48, 1385-1395, doi:10.1038/ng.3672 (2016).
  2. Nicetto, D. et al. H3K9me3-heterochromatin loss at protein-coding genes enables developmental lineage specification. Science 363, 294-297, doi:10.1126/science.aau0583 (2019).
  3. Chen, M. W. et al. H3K9 histone methyltransferase G9a promotes lung cancer invasion and metastasis by silencing the cell adhesion molecule Ep-CAM. Cancer Res 70, 7830-7840, doi:10.1158/0008-5472.CAN-10-0833 (2010).
  4. Harr, J.C., et al. Loss of an H3K9me-anchor rescues laminopathy-linked changes in nuclear organization and muscle function in an EDMD model. Genes & Dev. 34, 560 - 579. doi: 10.1101/gad.332213.119. (2020).
  5. Methot, S.P., Padeken, J., et al., H3K9me selectively blocks transcription factor activity to ensure differentiated tissue integrity.  In final revision, Nat Cell Biol(2021).
September 17, 2021
Dr. Santiago Claramunt, Associate Curator of Birds, Department of Natural History, Royal Ontario Museum & Assistant Professor, Department of Ecology and Evolutionary Biology, University of Toronto
“Integrative approaches to the study of bird diversification” RECORDING
Phylogenetic approaches are revolutionizing the study of macroevolution but inferences about diversification require accurate time-scaled phylogenies and attention to the fundamental causal processes. Here I show how we can make progress in both fronts using bids as an example. I show new approaches for the calibration of molecular clocks and how new avian time-trees reveal a striking correlation between global temperatures and diversification rates. Then, I show how dispersal ability can be estimated from wing shape and explore the relationship between dispersal ability and diversification rates. These new approaches have great potential for further our understanding of the process of diversification.
I was born and raised in Uruguay, where I became interested in science and nature, and obtained a BSc in Biology. I moved to the USA for doctoral studies at Louisiana State University, followed by a postdoctoral position at the American Museum of Natural History in New York. After teaching biogeography and evolutionary biology for two years in Peru, I moved to Toronto where I am Associate Curator of Birds at the Royal Ontario Museum and Assistant Professor—Status Only—at the Department of Ecology and Evolutionary Biology of the University of Toronto.
September 10, 2021
James Santangelo, PhD Student (Robert Ness & Marc Johnson Supervisors)
Parallel adaptation to the world’s urban jungles
Urbanization dramatically transforms environments in ways that alter the evolution of life. We examined whether global urbanization drives convergent environmental change and parallel evolution by sampling 110,019 white clover plants from 6,169 populations in 160 cities spanning diverse climates. Plants were assayed for hydrogen cyanide—a Mendelian antiherbivore defence that also affects tolerance to abiotic stressors. Urban environments were consistently hotter, less vegetated, and had more impervious surfaces than nonurban areas, which were associated with the evolution of phenotypic clines in 47% of cities throughout the world. Sequencing 520 genomes from 26 cities revealed that parallel clines were best explained by adaptive evolution, and environmental analyses showed that variation in HCN clines was explained by multiple interacting environmental factors. Our results demonstrate that ongoing urban environmental change is leading to parallel evolution globally.
Dr. Jimena Leyria, PostDoctoral Fellow (Angela Lange Supervisor)
A bite, a blood cocktail, and successful reproduction: control of egg-laying in a major vector of Chagas Disease
In the blood-sucking Rhodnius prolixus, a vector of Chagas disease, the nutrients incorporated by a blood meal have a high epidemiological impact since in adult mated females, each meal results in a bout of egg laying, and thereby the production of hundreds of offspring. In insects, insulin-like peptide (ILP) signalling along with the target of rapamycin (ToR) are involved in detecting and interpreting nutrient levels. By means of RNA-Sequencing we have examined how a blood meal influences mRNA expression of the ILP/ToR signalling pathway in key tissues involved in reproduction (fat body and ovaries). Although there is an up-regulation of the genes involved in ILP/ToR signalling in unfed insects, western blot analysis reveals that this signalling is only activated after a blood meal, i.e. phosphorylation of proteins. Immunofluorescence and RNA interference (RNAi) studies suggest that during the unfed condition, FoxO signalling may be responsible for the up-regulation of transcripts involved in the ILP/ToR signalling cascade. Moreover, exogenous insulin stimulates protein phosphorylation in the fat body and ovaries from unfed insects, suggesting that those females are in a sensitized state and respond to food by rapidly activating ILP signalling. Also, by RNAi and ex vivo assays we show that ILP/ToR pathway is involved in juvenile hormone (JH) synthesis and release, a hormone that coordinates the synthesis of yolk protein precursors by the fat body, which in turn influences the numbers of eggs laid per female. Our study reveals a network of regulatory pathways implicated in reproductive performance. These analyses serve as a starting point for new investigations that increase the chances of developing novel strategies for vector population control by translational research, with less impact on the environment and more specificity for a particular organism.
Sep 10, 2021
James Santangelo
PhD Student
Parallel adaptation to the world’s urban jungles. POSTER
Sep 10, 2021
Dr. Jimena Leyria
Postdoctoral Fellow
A bite, a blood cocktail, and successful reproduction: control of egg-laying in a major vector of Chagas Disease. POSTER
Sep 17, 2021
Dr. Santiago Claramunt,
Royal Ontario Museum
Integrative approaches to the study of bird diversification. POSTER. RECORDING
Dr. Sanja Hinic-Frlog
Sep 24, 2021
Dr. Susan Gasser,
ISREC – Swiss Institute for Experimental Cancer Research
How heterochromatin preserves genome stability and tissue identity in worms. POSTER. RECORDING
Dr. Mark Currie
Oct 1, 2021
Dr. Cassidy D'Aloia
Genetic approaches to uncovering marine connectivity. POSTER. RECORDING
Dr. Bailey McMeans
Oct 8, 2021
Dr. Maitreya Dunham,
University of Washington
Taking yeast experimental evolution out of the lab and into classrooms and breweries. POSTER. RECORDING
Dr. Alex Nguyen Ba
Oct 22, 2021
Dr. Matt Smear,
University of Oregon
Neural correlates of time and place in the olfactory bulb of freely-moving mice
Dr. Arbora Resulaj
Oct 29, 2021
Dr. Kari Segraves,
Syracuse University
The evolutionary ecology of species interactions. POSTER. RECORDING
Dr. Marc Johnson
Nov 5, 2021
Dr. David Baltrus,
University of Arizona
Developing Phage Derived Bacteriocins as Strain Specific Antimicrobials
Dr. Marcus Dillon
Nov 12, 2021
Dr. Otso Ovaskainen
University of Helsinki
Joint species distribution modelling: how to make more out of community data? POSTER. RECORDING
Dr. Helene Wagner
Nov 19, 2021
Dr. Satoru Miura,
University of California San Francisco
Why the world stands still when we move our eyes - Mechanistic insights from mouse visual. POSTER. RECORDING
Dr. Baohua Liu
Nov 26, 2021
Dr. Marian Schubert,
Norwegian University of Life Sciences
Evolution of temperate adaptations in grasses: Insights from molecular and macro-evolutionary studies. POSTER. RECORDING
Dr. Katharina Braeutigam
Dec 3, 2021
Dr. Katie Plaisance,
University of Waterloo
The Science of Team Science: How to Foster Productive Collaboration in Interdisciplinary Science Teams POSTER
Grad Students
Dec 10, 2021
Dr. Pierre Legendre,
Universite de Montreal
Temporal beta diversity: identify sites where species communities have changed in exceptional ways
Grad Students