Single Molecules Affect Complex Behaviors in Animals — And Humans

Animal and human behavior is complex and clearly is influenced by the actions of others and by past life experiences. For that reason, many people have been skeptical of the hypothesis that behavior might be influenced strongly by simple genetic factors. Recent findings challenge this skepticism.

In two Austrian studies of fruit flies, researchers found that a specific protein that is made in 2% of male neurons, but not in female neurons, affects a complex sequence of courtship behavior in response to female pheromones. When production of this single protein in males is abolished experimentally, they no longer engage in courtship behavior; when the protein is produced experimentally in females, they act like males and engage in courtship beh…