SEMINAR: MBF STUDENT SEMINAR **TODAY @ 1PM*** DAVID DAYAN & ANDREW KOUGH

[Pam Harris <pharris@rsmas.miami.edu>]

 

MBF Student Seminar Series

 

David Dayan

Advisor: Dr. Margie Oleksiak

 

“Phenotypic Plasticity and Adaptation in Fundulus Muscle Gene _expression_”

Temperature profoundly affects biological systems across all levels of organization. Over generational time, species become evolutionarily adapted to specific thermal environments. Additionally, individual organisms may reversibly modify their phenotype in response to a thermally variable environment in a process termed phenotypic plasticity. The interaction between these two processes, evolutionary adaptation and phenotypic plasticity, is complex and contentious. We utilize Fundulus glycolytic muscle physiology to address this issue. We conducted a microarray analysis of muscle gene _expression_ using three populations of Fundulus acclimated to three different temperatures. Analysis of gene _expression_ reveals a thermal acclimation response. Using a phylogenetic comparative analysis demonstrates adaptive variation in gene _expression_ among populations from different thermal environments. Interestingly, phenotypic plasticity and evolution appear to operate primarily orthogonally. More genes, however, exhibit both a plastic response and adaptive variation than expected by chance alone. Also, both the magnitude and function of the adaptive variation in gene _expression_ is dependent on acclimation temperature, demonstrating the importance of gene-by-environment interactions. Finally, a functional analysis of gene _expression_ provides novel, testable hypotheses regarding adaptation of muscle physiology.

 

Andrew Kough

Advisor: Dr. Claire Paris

 

“The in situ swimming behavior of spiny lobster (Panulirus argus) postlarvae”

Caribbean spiny lobster (Panulirus argus) spends 5 to 9 months at sea as pelagic larvae.  The final pelagic stage of P. argus is a non-feeding and rapidly swimming postlarva.  During up to two weeks as a post-larva, spiny lobsters must find and settle on nursery grounds.  Postlarvae come into Biscayne Bay during nocturnal flood tides at the new moon, yet the environmental cues leading them onshore remain largely unknown.  We adapted a Drifting In Situ Chamber (DISC), designed to record the swimming and orientation behavior of marine larvae set adrift at sea while sensing environmental factors, to work at night and modified its behavioral arena to observe lobster postlarvae.  Deployments offshore the Fowey Rocks NOAA buoy provided detailed physical data to describe potential cues being used by P. argus.  In this proof-of-concept study, 78% of the individual postlarvae tested in the DISC had significant directional swimming.  Population-level orientation was towards the south-southwest (188o, Rayleigh’s R = 0.5742, p < 10-5). This orientation was not significantly correlated with currents but with both the tidal phase and the wind direction. Postlarvae oriented with the wind during ebb flow and against the wind during flood.  This behavior may allow lobsters to smell a coastal environment with the ebb flow and harness the nocturnal sea-breeze to head towards shore.

 

 

 

FRIDAY, JANUARY 18, 2013

1:00pm

RSMAS campus, S/A 103

Pamela Harris

Marine Biology and Fisheries

Rosenstiel School of Marine & Atmospheric Science

University of Miami

4600 Rickenbacker Causeway/SLAB-118

Miami, FL 33149

(305) 421-4176

fax - (305) 421-4600

pharris@rsmas.miami.edu  

 

http://www.rsmas.miami.edu/academics/divisions/marine-biology-fisheries/