Scientists Genetically Engineered “Fearless” Mouse

Japanese scientists had genetically engineered a mouse that has no fear of cats simply by controlling its sense of smell:

By tweaking genes to disable certain functions of the olfactory bulb — the area of the brain that receives information about smells directly from olfactory receptors in the nose — the researchers were able to create a “fearless” mouse that does not try to flee when it smells cats, foxes and other predators.

In studying the genetically modified mouse, the researchers have concluded that the evasive behavior exhibited by mammals when they smell predators may be genetically hardwired into the olfactory bulb from birth, and not learned through experience as commonly believed.

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