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A sweet collaboration

Small Grant for Exploratory Research teams Fabry and Hofmann to develop genomic resource for Antarctic pteropod

Gretchen Hofmann is making something of a cameo appearance at McMurdo Station this season.

The marine molecular biologist from the University of California Santa Barbara is on the Ice working with Victoria Fabry, a leading expert on ocean acidification, to develop DNA sequence and molecular resources for the Antarctic pteropod Limacina helicina.

The tiny marine snail is the focus of a three-year project led by Fabry. Her team is collecting specimens of the animal, and testing how changes in seawater chemistry may affect its physiology, particularly its ability to calcify, under higher acidic conditions predicted within the next century.

Hofmann and Fabry are collaborating on the separate DNA project through a National Science Foundation Small Grant for Exploratory Research (SGER). Acquiring the DNA sequence of the pteropod will allow the researchers to develop a DNA microarray to profile the sea snail’s gene expression, how it responds to climatic changes at the genetic level.

Hofmann has used a similar genomic technique to study how certain Antarctic fish respond to variations in temperature. (See the Dec. 31, 2006 issue of The Antarctic Sun Link to PDF file .)

Genomics is a field of study that examines the expression of all genes in an organism. Gene expression is the process by which a gene’s DNA sequence codes for the proteins that make up cell structures and perform cell functions.

A DNA microarray is one particular type of genomic tool. It is a collection of microscopic DNA spots attached to a solid surface — about the size of a stick of gum — that form an array for profiling gene expression. This allows scientists to monitor expression levels for thousands of genes simultaneously. Before, they could only study one gene at a time.

Said Hofmann, “We want to know if organisms have resiliency: Do they have abilities to compensate or adapt to make it through this coming environmental bottleneck?”

Students in her laboratory have also dabbled in studying genetic responses to multiple factors like heat stress and acidification on sea urchin larvae, assisted by data available from the Purple Sea Urchin Genome Project.

“You’re working with not a very charismatic organism, but one that can tell you a lot about what’s going on in the oceans,” Hofmann said.

Genetically, the animal “downregulated” genes associated with physiological development, and “upregulated” those for defending against the stresses. In other words, it focused its genetic resources to survive, sacrificing normal development. Hofmann’s lab found that the animals were particularly vulnerable to thermal stress in more highly acidic seawater.

Now, they want to turn the same tools on the Antarctic pteropod.

It’s very much exploratory science, Fabry said, but may prove to be a key project. “I think it will help jumpstart some important work in the genomics of pteropods.”

Said Hofmann, “It’s a challenging and exciting time for environmental science.” 

Return to main story Ocean Acidification

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Curator: Peter Rejcek, Antarctic Support Contract | NSF Official: Winifred Reuning, Division of Polar Programs