Biology Majors Meeting

Biology Majors Meeting

September 11, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Informational Meeting for current and prospective Biology Majors

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Why Did Americans Stop Eating Locally?

Why Did Americans Stop Eating Locally?

September 11, 2014 7:00 PM  – 9:00 PM
Sills Hall, Smith Auditorium

In his talk Matthew Booker will explore why urban Americans radically changed their diets in the twentieth century. Tracing the American diet from local oysters to long distance burgers, he will suggest ways we can learn from this history as we rethink today's and tomorrow's food.

Matthew Booker is an associate professor of History at North Carolina State University, and a specialist in Environmental History and Western North American History.

For more information on this event, please see the website.

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Stem Cell Tumors: Getting Their Fix on the Fly

Stem Cell Tumors

September 18, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 016

Michelle Markstein, Assistant Professor, Biology Department, University of Massachusetts, Amherst

Research Interests: Stem cells and cancer

The Markstein lab seeks to understand the stem cell properties of cancer cells with the goal of developing new cancer therapeutics. We focus on cell-cell interactions within the stem cell microenvironment and on the plasticity of stem cell genome architecture. Our approach is in vivo, using the fruit fly Drosophila melanogaster to screen for anti-cancer drugs and drug targets.

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Developing a broader perspective for marine communities in an area of climate change: insights from the Galapagos Islands

Developing a broader perspective for marine communities in an area of climate change

September 25, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Jon D. Witman, Professor, Biology Department, Brown University

Research Interest:
My research is directed toward understanding the dynamics of populations and communities living in marine hard substrate habitats. Our lab is conducting research focused around three themes: 1) physical forcing of marine benthic ecosystems, 2) studies on the origin vs. the maintenance of pattern, and 3) marine biodiversity. How community structuring processes vary with scale is a consideration that pervades all aspects of our research.

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Selective Attention and Memory Across Development

Selective Attention and Memory Across Development

October 9, 2014 4:00 PM  – 5:30 PM
Kanbar Hall, Room 107

Julie Markant, Postdoctoral Candidate, Brown University

From the first year of life onward, infants and children visually explore the world around them to gather information about their environment. Some of this information will be remembered, and some will be lost. The information that is remembered is carried forward and becomes integrated with all that they encounter in the months and years to come. In this talk I will present research demonstrating that these two processes, selective attention and memory, are functionally coupled early in development and that improvements in selective attention may contribute to enhanced efficacy of memory encoding. In the first part of my talk I will discuss behavioral and eye tracking studies demonstrating that attention orienting mechanisms involving both target enhancement and distractor suppression promote enhanced memory encoding both in infancy and across development. Second, I will discuss genetic work examining biological correlates of individual differences in developing attention and learning & memory systems. This work has revealed that COMT genotype, and thus variations in prefrontal dopamine signaling, may be a common biological substrate contributing to individual differences in both selective attention and learning during infancy.

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Multiple Stable States: Theory and Evidence

Multiple Stable States

October 9, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

One of the most vexing problems in ecology is how distinctly different communities, such as mussel beds and seaweed stands that occur on rocky shores in Maine, can occur in the same ecosystem. These communities often persist for long periods, yet small, temporary shifts in environmental conditions can cause an unexpected tipping of the system and one type of community may be replaced by another. How can alternative communities be both persistent and yet so susceptible? The theory of these systems, known as multiple stable states, is well understood, but whether multiple stable states actually exist in nature has remained a hotly debated subject and, not surprisingly, definitive examples continue to be elusive. The past decade has seen resurgent interest in the topic because of large-scale changes in the species composition of many ecosystems around the globe and the extent to which anthropogenic activities and climate change may underlie these sudden shifts. The occurrence of multiple stable states has implications for how we manage ecosystems and our basic understanding of the roles of historical and contemporary processes in determining patterns of organismal distribution and abundance. I will present the results from the past 18 years of an ongoing project investigating whether rockweed stands and mussel beds represent alternative community states in sheltered bays of the Gulf of Maine.

Dr. Steve Dungeon is Professor of Biology, at the California State University, Northridge.  He received his PhD from the University of Maine in 1992. His research interests focus on the unique biological features of clonal algae and invertebrates, the evolution of life history and morphological traits and how these traits influence the dynamics of the communities in which they live. The temperate rocky intertidal zone is the experimental system used to explore these concepts.

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Epigenetic Defense Mechanisms: Coping with Transposable Elements in the Drosophila Genome

Epigenetic Defense Mechanisms

October 23, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Sarah Elgin, Department of Biology, Washington University, St. Louis

Eukaryotic genomes contain high levels of transposable elements (TEs - retroviruses and DNA transposons) and their remnants, DNA that is commonly packaged for silencing in heterochromatin. Work in the fruit fly Drosophila melanogaster has suggested how such silencing occurs at the nucleosome level, utilizing an alternative pattern of histone modification with association of heterochromatin-specific proteins, notably HP1. This mechanism appears to be conserved from the yeast S. pombe to humans. Work in mice (by Jirtle and others) has shown that TE silencing can be sensitive to diet. Correct targeting of heterochromatin formation is critical, as inadvertent silencing will lead to loss of gene function, with deleterious effects (example - triplet repeat mutations in humans, such as Fragile X). In flies, both the type and density of repetitious elements (primarily transposons) appear to be critical. We find that Piwi (the piRNA binding protein) is critical for HP1a deposition at some TEs. Piwi appears to play a role in setting up heterochromatin structure in the early embryo, but is not required to maintain silencing in the eye linage. Alternative mechanisms may be involved in targeting simple repeats. Further work will be needed to understand these complex systems, which are critical to maintaining the integrity of the genome

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Exploring with Drosophila: Lessons Learned on a Journey through the Fly Genome

Exploring with Drosophila

October 24, 2014 12:30 PM  – 3:30 PM
Visual Arts Center, Kresge Auditorium

2014 President's Science Symposium. Key note speaker. Sarah Elgin, Department of Biology, Washington University, St. Louis

The years since 1953 have been an exciting time, as genetics has embraced first molecular biology and then genomics approaches. In this talk I will reflect on my own journey, and the broader lessons learned from a career studying chromatin structure and epigenetic mechanisms. During this time the puzzle posed by our very large eukaryotic genomes has been resolved by the recognition that our genomes are largely made up of transposable elements (TEs) and their remnants, bits of DNA derived from invading viruses and the like. Thus packaging up the DNA, which is done by generating a protein-DNA complex called chromatin, is necessary not only to fit all of the DNA into the nucleus, but also to maintain most of the genome in a silent state.

Our work in flies identified one of the key proteins used in silencing, Heterochromatin Protein 1 (HP1), which is conserved from yeast to humans. Chromatin-based regulatory mechanisms now referred to as "epigenetics" are dependent on the underlying DNA organization, including the distribution of those TEs. Our good ideas that have helped to resolve this puzzle have always come from putting together inputs from multiple sources. Good communication, both among scientists and with the larger community, is essential for our continuing efforts to understand how life works.

Kresge Audiorium 12:30 p.m. followed by Student Presentations.  The Student Summer Poster Presentations: 3:00 - 5:00 Morrell Gymnasium.

This talk will also be live streamed on Bowdoin's Live Webcasts page.

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Intra- and interspecific differences in physiological indicators of biogeographical limits for decapod crustaceans

Intra and interspecific differences in physiological indicators of biogeographical limits for decapod crustaceans

October 30, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Markus Frederich, Professor, Biological Sciences, University of New England

Research Interests:
Invertebrate physiology, crustacean biology, adaptations to environmental stress, regulation of energy metabolism

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Ben Ewen-Campen: "Stem Cell Genes in Germ Cells and in Brains"

Ben Ewen-Campen

November 6, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Ben Ewen-Campen, Postdoctoral Candidate, Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Perrimon Lab.
As an undergraduate, I studied developmental biology with Scott Gilbert at Swarthmore College. I then worked as a technician in Doug Emlen's lab at the University of Montana, studying the development of beetle horns, and in 2014 I received my PhD from Harvard University, working in Cassandra Extavour's lab on the embryonic specification of germ cells. In the Perrimon lab, I am studying long-range regulation of germline stem cell proliferation, and I am also interested in developing new tools for manipulating gene expression.

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Wendy Gilbert: "New Regulatory Functions for Ancient RNA-Modifying Enzymes"

Wendy Gilbert

November 13, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Wendy Gilbert, Professor of Biology, MIT

The proteins of a cell are the primary determinants of cellular form and function. Wendy Gilbert, professor of biology at MIT, examines how regulation of the proteome is therefore the ultimate goal of signaling pathways that connect cell physiology to internal and external environmental cues. Her studies focus on the molecular mechanisms and physiological functions of translational control of gene expression using genome-wide translation state profiling, molecular genetics, and biochemistry.

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Robin Hopkins: "Speciation Causes Flower Color Evolution in a Texas Wildflower"

Robin Hopkins

November 20, 2014 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Robin Hopkins, professor of organismic and evolutionary biology at Harvard University, examines the process of speciation as a major goal of evolutionary biology and the role of natural selection in causing diverging populations to become species. She addresses these goals by investigating fundamental questions of evolutionary biology such as: What is the genetic basis of adaptations? What is the role of migration and genetic drift during the evolution of traits? What is the strength of selection acting on an adaptive allele? And what is the mechanism underlying selection?  

Professor Hopkins' work incorporates molecular biology, population genetic analyses, and field-based selection experiments to address these questions. Her research examines speciation in plants, predominantly focused on reinforcement, the process in which reduced hybrid fitness generates selection for the evolution of reproductive isolation between emerging species. She uses an interdisciplinary approach that incorporates functional molecular biology experiments, population genetic analyses.

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David Angelini: "Having it both ways: The Developmental Genetics of Dimorphisms in True Bugs"

David Angelini

December 4, 2014 4:00 PM  – 5:15 PM
Druckenmiller Hall, Room 020

David R. Angelini, assistant professor of Biology at Colby College, addresses the growing field of evo-devo and the interest in the developmental and molecular genetic aspects of morphological evolution. He examines how the use of developmental genetics, molecular biology, morphometric and phylogenetic methods help understand the interactions and functions of genes and their networks in the evolutionary histories that have led to animal diversity.

Note: This talk will also be live streamed on Bowdoin’s Live Webcasts page.

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