Zebrafish, part of the minnow family, are often used in genetic scientific experiments due to their fully sequenced genome, well-understood, easily observable behavioral development, quick reproduction process (egg to larvae in 3 days), similar reaction to humans in toxicity testing and translucent bodies. Thus many genetic discoveries made in zebrafish have a great possibility of leading to similar discoveries in humans. The recent discovery of an identifiable aggression-boldness gene in zebrafish was particularly exciting for these reasons.
In zebrafish, the gene fgfr-1 regulates the histamine levels, and thus the many behavioral traits, of the brain. This unique gene has been pinpointed as the potential regulator of the characteristics of boldness, exploratory behavior and aggressiveness. "Aggression-boldness syndrome" is characterized by above-average boldness. Also known as proactive behavior, this syndrome was identified in a certain strain of zebrafish, manifested in excess aggressiveness, little intimidation by 'predators' and more adventurous and explorative behavior.
Within this strain of zebrafish, scientists notes a mutation in it's fgfr-1 gene, making it more sensitive to FGF. Consequently, their brain histamine levels were lower than average, giving them abnormal appetite regulation, sleep and attention. With simple pharmacological treatments to increase their histamine levels, this special strain of fish was able to recover normal zebrafish behavior, returning average boldness-aggression levels.
Scientists have now identified fgfr-1 as one gene that directly effects the boldness and aggressive behavior of zebrafish. While environmental factors also influence such behavior, scientists agree that this gene seems to regulate the basic level of proactivity. Hopefully the links that scientist uncover between fgfr-1, histamine levels and animal behavior, will illuminate how humans also regulate aggression and boldness behaviors.