First Application of Molecular Techniques to Understanding Diapause Regulation in Marine Copepods

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A multiple opening-closing net and environmental sensing system (MOCNESS), a mutiple net system designed to collect depth-stratified zooplankton samples.

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Calanus finmarchicus (stage C5) collected during a MOCNESS tow.


Principal Investigators: 
Ann Tarrant (WHOI Biology), Mark Baumgartner (WHOI Biology)

Collaborators:  Tim Verslycke
(WHOI Biology), Catherine Johnson (University of New Hampshire), and John Stegeman (WHOI Biology)
.

Planktonic marine copepods are the most abundant group of animals in the sea, but little is known about the factors that control important stages of their life history. Calanus finmarchicus, the dominant large copepod in the temperate North Atlantic, has a complicated life history that includes a resting phase, or diapause. Because of their great abundance and substantial energy content (primarily due to their lipid reserves built in preparation for diapause), C. finmarchicus provides a critical link between phytoplankton production and higher trophic levels, including fish, seabirds, and whales. Thus, diapause in C. finmarchicus has important implications for marine ecosystms, yet virtually nothing is known about what regulates the onset, duration, and termination of C. finmarchicus diapause.  Unfortunately, C. finmarchicus does not initiate diapause in captivity, so laboratory studies are impossible.  We will use molecular techniques to identify genes that are differentially regulated in diapausing versus non-diapausing (active) C. finmarchicus juveniles. These genes will allow us to speculate about the intrinsic mechanisms that control diapause.  We will use two key techniques:  suppressive subtractive hybridization (SSH) to identify candidate genes involved in the regulation of copepod diapause, and quantitative real-time polymerase chain reaction (qPCR) to quantify the expression of specific genes. Our multidisciplinary approach combines researchers with backgrounds in molecular biology, crustacean endocrinology and physiology, and copepod ecology. To the best of our knowledge, this will be the first study to use measures of gene expression to investigate diapause regulation in an ecologically critical marine species.

Support for this project provided by the WHOI Ocean Life Institute.


Publications and Presentations
Aruda, A.M., M.F. Baumgartner, A.M. Reitzel, and A.M. Tarrant.  Heat shock protein expression during stress and diapause in the marine copepod Calanus finmarchicusJournal of Insect Physiology (Special Issue on Invertebrate Diapause).  in press.

Tarrant*, A.M., M.F. Baumgartner*, T. Verslycke, and C.L. Johnson.  2008.  Differential gene expression in diapausing and active Calanus finmarchicus (Copepoda).  Marine Ecology Progress Series 355:193-207.  *These two authors made equal contributions to this paper.

Tarrant, A.M., M.F. Baumgartner, T. Verslycke, and C.L. Johnson. 2008. Molecular characterization of diapause in the marine copepod Calanus finmarchicus. Summer Meeting. American Society of Limnology and Oceanography. St. Johns, Newfoundland, Canada. June 8-13, 2008.


 

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Last updated April 19, 2011
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