For worms, choosing when to search for a new dinner spot depends on many factors, both internal and external: how hungry they are, for example, how much oxygen is in the air, and how many other worms are around. A new study demonstrates this all-important decision is also influenced by the worm's genetic make-up.
In the simple Caenorhabditis elegans nematode, the researchers found that natural variations in several genes influence how quickly a worm will leave a lawn of bacteria on which it's feeding. One of the genes, called tyra-3, produces a receptor activated by adrenalinea chemical messenger involved in the 'fight-or-flight' response. The findings appeared online March 16, 2011, in the journal Nature.
"What's encouraging to us about this story is that molecules related to adrenaline are implicated in arousal systems and in decision-making across a lot of different animals, including humans," says Howard Hughes Medical Institute investigator Cornelia Bargmann of Rockefeller University in New York, who mentored the work of graduate student Andres Bendesky. These parallels between diverse species suggest that aspects of our decision-making abilities have ancient evolutionary roots.
Six worms on a small lawn of bacterial food (circle). Occasionally, a worm leaves the food to explore the surrounding environment. Video: Bendesky et al. Nature
C. elegans thrive in agricultural settings, such as orchards and crop lands, feeding on bacteria from rotting fruits and vegetables. But eating in this environment is tricky: the worms encounter many bacterial species that are difficult to digest or even toxic. "The worms need to somehow evaluate a whole spectrum of conditions to decide whether they want to try this food source or go out and look for a better one," Bargmann says.
The great scientific advantage of using C. elegans to study complicated behavioral processes such as decision-making is that the w
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Howard Hughes Medical Institute