Narrator: This is Science Today. Researcher Cori Bargmann of the University of California, San Francisco studies our sense of smell. She works with a laboratory worm called by its Latin name c. elegans.

Bargmann: And it turns out that c. elegans, our little organism, is wild about buttery compounds.

Narrator: Bargmann found that by changing one gene in the little worm, she could make it ignore the smell of butter. She believes that means that all animals, including humans, are born with specific receptors for every individual smell. Of course, the human sense of smell is far more complex than that, but Bargmann says you have to start somewhere.

Bargmann: The idea in studying c. elegans, as in studying any model organism, is to develop a sense of what the ground rules are, and then either we or other groups can use this information and ask it in mammals. So there's every reason to think that the way a mouse smells the world, for instance, is much more similar to the way that a human smells the world than is the way a worm smells the world.

Narrator: For Science Today, I'm Steve Tokar.