Campus Currents

Jump Start From a tiny flea comes a big breakthrough by Beth Potier Illustration by Jason Raish

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The water flea is a tiny creature that, when threatened by a predator, grows exaggerated spines, neck-teeth and helmets. But its ability to shape-shift is only part of why Daphnia pulex is one of the biggest genomics stories of the year.

In January, an international consortium that included UNH researchers published a complete description of the water flea's genome in the journal Science. Much of the buzz around the Daphnia genome concerns its size, says W. Kelley Thomas, Hubbard Professor in Genomics and director of the Hubbard Center for Genome Studies. With 31,000 genes, this tiny creature has more than any other animal with a complete genome sequence, including humans, who have around 25,000.

Even more exciting is how this genome will lead to greater understanding of the interaction between genes and the environment. That's because from an environmental perspective, Daphnia is the best-studied organism on the planet. Scientists know how this species responds to pollution, predators and day and night, making it an important species for ecological and evolutionary research.

Now scientists can start to study which genes help the water flea—abundant in freshwater reservoirs worldwide—adapt to environmental stresses and predators. Because scientists already know so much about how Daphnia responds to, for instance, heavy metal pollution in its natural environment, they can now probe the genetics behind those adaptations. "You could determine what genes get turned on, and at what concentrations of a substance," says Thomas.

Thomas and others now theorize that Daphnia's massive catalog of genes is behind the organism's ability to change its shape in response to predators.

The project helped launch the science careers of many UNH undergraduate and graduate students. It also reached across departments: As the science of genome sequencing evolved in the past decade to use "fewer pipettes and more computers," says Thomas, the center forged strong bonds with computer science professors R. Daniel Bergeron and Philip Hatcher.

Thomas says that unlocking the genomic mysteries of this tiny creature is a major step forward for the relatively new field of environmental genomics. "This is a big deal in biology. It's a new model species, and I think it will have a major impact for a long time," he says. "It's probably the best thing we've done here at the Genomics Center."