Many behaviors are the output of a complicated web of interactions in the brain. Some of these behaviors, such as mate choice, have important consequences, yet our understanding of the brain mechanisms underlying this critical behavior is remarkably minimal. This project will use molecular techniques to explore the neural control of mate preference behavior by examining where in the brain specific genes associated with preference behavior are expressed, and whether behavior can be manipulated by manipulating gene expression. The research tests specific hypotheses drawn from recent work by the PI that identified candidate genes for female preference behavior in a classic mate choice system (the swordtail fish). Using pharmacological, molecular and neurobiological techniques, the investigator will test whether these genes (i) are directly involved in mediating preference response, (ii) are expressed in a neural pathway distinct from other social neural behavior networks, and (iii) account for inter-individual and inter-specific variation in female preference behavior. The expected outcome of this research will include the first functional test of candidate gene influence on preference behavior, elucidation of the neural circuitry governing preference behavior, and the first mechanistic comparison of choice versus coercion mating systems. The results of this research will shed light on the dynamic control of social interactions with the opposite sex by the vertebrate brain. Such research is a fundamental first step in understanding the influence of genes on human behavior, and will likely be a catalyst for further studies in human. The project also represents a major advancement in the field of animal behavior and sexual selection. The research is at the forefront of sexual selection studies by identifying potential molecular and neural targets for sexual selection. The project will also provide broad educational impacts through the integration of results into an undergraduate course in Animal Behavior.
This research represented the first application of a behavioral genomics approach to mate choice behavior in vertebrate animals and provided the initial characterization and functional analysis of genes and brain regions involved in visual mate discrimination. We initially conducted a microarray experiment with a model species for sexual selection studies in the lab (a swordtail fish, Xiphophorus nigrensis) to identify genes expressed in the brain during mate choice encounters relative to other social contexts. Once we identified the suites of genes uniquely expressed under mate choice relative to other social encounters we conducted subsequent behavioral genomic experiments to (1) determine if expression of these genes at the whole brain level predicted individual variation of female preference behavior, (2) identify specific brain regions linked to preference behavior by characterizing significant correlations between female preference behavior and the expression of these candidate genes in specific brain regions associated with learning and memory, (3) functionally test the relationship between these genes and behavior by pharmacological manipulation of these candidate gene pathways resulting in modification of female preference behavior, and (4) determine if covariance patterns of whole brain gene expression and female behavior was conserved in a closely related fish species with a different mating system. The candidate genes linked to female preference behavior are functionally linked to synaptic plasticity processes in the brain (which are associated with learning and memory). This genetic pathway is distinct from other genetic pathways linked to other social behaviors (such as oxytocin pathway and social affiliation behavior). Intellectual merit of this research involved 12 peer-reviewed publications, a ground-breaking approach to studying mechanisms of sexual selection in the brain, and the identification of unique genetic pathways regulating social behavior. Broader impact activities supported by this award included education benefits to both undergraduate and graduate students as the PI incorporated behavioral aspects of this research in her undergraduate course "Principles of Animal Behavior", and trained 27 undergraduates (16 women, 3 hispanics and 2 African Americans), two graduate students, and two postdocs during this research period. As a direct result of her research-oriented Animal Behavior class, two African American undergraduates started conducting independent research in her lab- representing their first endeavor into scientific research outside the classroom. The PI has also given outreach talks including STEM talks at schools, and larger (200-100 attendees) "Darwin Symposia" talks open to the public at three different universities and three local venues.
