Scientific Report 2008
Molecular Biology of Innate Behavior
L. Stowers, P. Chamero, K. Flanagan,
D. Logan, T. Marton, F. Papes
Every breath samples
the environment for olfactory chemical information, determining the quality of food,
warning of danger, and confirming safety. The neurons that mediate olfaction are
of 2 types: those that mediate an evocative perception that varies with an individual's
experience and those that regulate stereotyped innate social behaviors such as aggression
and mating in response to pheromones. The biochemical nature of the pheromone code
that induces innate behavior in mammals is not known, and the sensory system responsible
for the detection of pheromones is a matter of controversy. We expect that elucidating
the stimulating ligands and responsive neurons will enable us to activate, study,
and identify the mechanisms underlying neural information coding of defined behaviors.
We recently isolated novel mouse pheromones
that mediate aggressive behavior and determined the identity of the aggression-promoting
chemosensory neurons. We have taken a unique approach to decode olfaction; we are
working forward from the behavioral activity to identify novel genetically encoded
pheromones. These pheromone proteins reproducibly activate a subset of accessory
olfactory neurons, enabling the molecular identification of those neurons that mediate
the aggression-promoting behavior. This step is a fundamental one for understanding
intraspecific communication in mammals and characterizing the neuronal circuit that
The response of an individual to pheromones
varies with the individual's age, sex, and dominance. We are using the purified
aggression-promoting pheromone of mice to understand this plasticity. Interestingly,
we found that whereas males have sensory neurons that respond to the pheromone,
the sensory neurons in females are not activated by this cue. This lack of response
suggests that males and females are sampling different features of the environment,
a difference that in turn leads to different behavioral outcomes.
Our progress in discovering the ligands
and sensory neurons that promote innate behaviors is enabling us to identify mechanisms
of neural information coding. We have compiled a unique set of resources that will
allow us to answer some of the fundamental unanswered questions about both specific
and more general aspects of the neural coding of innate behavior.
Chamero, P., Marton, T.F., Logan,
D.W., Flanagan, K., Cruz, J., Saghatelian, A., Cravatt, B.F., Stowers, L.
Identification of protein pheromones that promote aggressive behaviour. Nature 450:899,
Logan, D.W., Marton, T.F., Stowers,
L. Species specificity in
major urinary proteins by parallel evolution. PLoS ONE 3:e3280, 2008.