Biology Fall 2013

21 October: 

Erik Zettler, Ph.D.
Professor of Oceanography and Associate Dean for Institutional Relations and Research, Sea Education Association, Woods Hole
"Life in the 'Plastisphere': The Ecology of Plastic Marine Debris"

Research Summary: Plastic is now the most common form of marine debris and there is substantial public and scientific interest in this issue. Other than the known problems of entanglement and ingestion by fish, turtles, birds, and marine mammals, there are questions of contaminant transport and invasive species that could affect native communities and aquaculture operations. The microbial community that develops on plastic marine debris has been particularly poorly studied, but could play a role in nutrient cycling, plastic degradation, and the spread of potentially harmful microbes. SEA Semester students from colleges across the country have played a major role in plastic marine debris research, collecting and analyzing the most extensive data set on plastic marine debris in the world, with over 10,000 individual net tows in the Atlantic and Pacific oceans since the 1980s. There is a lot of plastic in the ocean, but intense public attention has encouraged a certain amount of media hype that creates misperceptions about the problem. SEA’s extensive data set allows student scientists to objectively examine and characterize the distribution and quantity of plastic in different parts of the ocean including the so called “Pacific Garbage Patch”.  [Host: Alexandra Purdy]

4 November: 

Ryan L. Earley, Ph.D.
Assistant Professor, Department of Biological Sciences, University of Alabama
“Integrating behavior, hormones, and life history towards understanding complex phenotypes”

Research Summary: The Earley laboratory uses a variety of fish species to understand the mechanisms underlying phenotypic variation, particularly aggressive and reproductive behaviors. More recently, we have capitalized on some extraordinary characteristics of a unique vertebrate model to explore the mechanisms that sculpt complex phenotypes, and how suites of phenotypic traits change in response to early-life environmental conditions and in response to selection. The mangrove rivulus is the only self-fertilizing, hermaphroditic vertebrate capable of producing offspring that are genetically identical to both the parent and all sibs.  This extraordinary reproductive strategy, coupled with occasional out-crossing, provides the opportunity to explore with unprecedented resolution both genetic and non-genetic bases of phenotypic variation in a vertebrate system. We combine field and laboratory investigations to understand the degree to which phenotypic traits (from endocrine profiles and life history characteristics to behavior) covary, the evolutionary implications of such covariance, and how the physical and social environments alter developmental trajectories of behavior, physiology, and sex. [Host: Ethan Clotfelter]

11 November: 

Bryan Monesson-Olson, Ph.D.
Post-Doctoral Research Associate, Biology Department, Amherst College. 
“Control Your Excitement: Inhibition of Escape Behavior in Zebrafish”

Research Summary: Escaping from dangerous situations is something all animals have to do. How they do it is a complex question. One group of inhibitory receptors, the GABAA receptors, regulates a long list of circuits and behaviors in vertebrates including escape behavior. Dr. Monesson-Olson studies how these receptors regulate escape behavior, and he uses zebrafish to study these questions. Using a combination of mRNA in situ hybridization, drug treatment, behavioral analysis, and now electrophysiology, he is unraveling how these circuits function or fail to function. [Host: Josef Trapani]

18 November: 

Lexi Brown
Ph.D. Candidate, University of Massachusetts at Amherst. 
"Small scales, big picture: allocation and limitation of carotenoid pigments in a female-ornamented fish"

Research Summary: Some animals use pigments called carotenoids to produce red, yellow or orange coloration. In addition, carotenoids may benefit the health or breeding potential of these animals. If carotenoids that are placed in the skin are unavailable for supporting health, body coloration might show an overall picture of how an animal is faring in its environment, e.g. a sick or poorly-fed animal might have dull color, while a healthy animal might be colorful. This is called “honest signaling”. Female signaling is rarely considered by researchers because males are usually the flashy, carotenoid-ornamented sex, and they use this signal to attract females. But what about cases in which females are ornamented, and males are dull? How a carotenoid-based ornament may have evolved in the female convict cichlid fish (Amatitlania siquia) is the focus of Dr. Brown’s research.  [Host: Ethan Clotfelter]

21 November, Thursday, 4:30 p.m., Merrill 4: 

Kevin J. Bender, Ph.D. 
Assistant Professor of Neurology, Ernest Gallo Clinic & Research Center Center for Integrative Neuroscience, University of California, San Francisco.
"New mechanisms for dopaminergic control of prefrontal learning"
http://keck.ucsf.edu/neurograd/faculty/bender.html

Research Summary: TBD.   [Host: Neuroscience Program, Josef Trapani]

2 December: 

Sevan Suni, Ph.D.
Darwin Postdoctoral Fellow, Organismic and Evolutionary Biology Program, University of Massachusetts, Amherst
“Conservation Genetics of Pollination Systems” 

Research Summary: Dr. Suni's research focuses on the evolutionary ecology of species interactions, effects of ecology and environmental change on genetic variation, and the application of population genetic information to conservation.  She use genomics, population genetics, observational data, and field experiments.  Her primary focus is on plant-pollinator interactions due to the central importance of pollinators both to ecosystem health and the global food supply. [Host: Ethan Temeles]

9 December: 

Terence Capellini, Ph.D.
Assistant Professor, Department of Human Evolutionary Biology, Harvard University
“When Evolution Hurts: Height, Arthritiis and the Control of Skeletal Development” 

Research Summary: Research interests: Modern humans and closely related ancestors display marked variations in many biological traits, although their genotypic basis remains largely unknown. Much of this variation is due to non-coding regulatory mutations. The Growth and Differentiation Factor 5 (GDF5) gene controls skeletal development and recent studies have shown that high frequency variants in GDF5 associate with height and osteoarthritis risk. Although these associations are highly replicated, the causal base pairs controlling these phenotypes remain unknown. Using transgenic and knockout mice, the Capellini lab discovered key GDF5 regulatory enhancers that control expression in separate skeletal structures, including growth plates or individual limb joints. These enhancers contain functional variants and reside in the genetic interval associated with height and arthritis risk. Molecular signatures suggest that a variant regulatory block at GDF5 has been the target of strong natural selection during recent human evolution, particularly in out-of-Africa populations. Past selection may have driven select human and Neanderthal regulatory variants to high frequency, with important consequences for the overall risk of arthritis in modern populations.

For More Information:  The Broad Institute, Cambridge: genomics, molecular genetics of disease, development: http://www.broadinstitute.org/history-leadership/founders/associate-members; The Boston Evolutionary Genomics Supergroup. [Host: William F. Zimmerman]

Last Updated:
24 February 2015 TLR