Sat, Nov 19, 2005 - Page 6 News List

Scientists identify `fear' gene in mice, research reports

STATHMIN Study shows that mice lacking this gene become daredevils and are unable to show fear in the face of predators or danger

THE GUARDIAN , LONDON

Fear is all in the genes: mice lacking the gene stathmin become daredevils, unable to show the appropriate fear of predators or dangerous situations, according to a report in the journal Cell.

"This is a major advance in the field of learning and memory that will allow for a better understanding of post-traumatic stress disorder, phobias, borderline personality disorder and other human anxiety diseases," said Gleb Shumyatsky, a professor of genetics at Rutgers University, New Jersey, who led the work.

"It will provide important information on how learned and innate fear is experienced and processed, and may point the way to apply new therapies," he said.

Shumyatsky conditioned fear into one group of normal mice and another lacking the stathmin gene by making them associate an electrical shock with a particular sound.

While both groups showed some fear by freezing immediately after the shock and, later, after hearing the tone, the researchers found that the stathmin-deficient mice reacted less strongly. They also showed less fear of open spaces, exploring the kinds of environments they would naturally avoid.

The work led on from Shumyatsky's discovery in 2002 of gastrin-releasing peptide, a gene active in parts of the brain which deal with learned fear. In the new study, he describes how stathmin controls both learned and innate fear.

"Biologically, innate fear is something that an animal does not have to learn," Shumyatsky said.

"It is often species-specific -- for example, mice are afraid of snakes, rats and cats. Basically animals often have inborn fear for their natural predators or certain body movements that are predator-like," he said.

On the other hand, learned fears are a result of an animal's experience.

Because fear plays an essential role in survival, memory for fear is easily established and resistant to being deleted.

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