RCN Collaboration: Environmental, Hormonal, and Genetic Mechanisms of Adaptive Behavior
Eva Fischer, a doctoral student at Colorado State University, participated in the Sociogenomics Initiative’s Laboratory Exchange program to facilitate collaborative research between the labs of RCN members Kim Hoke, Colorado State University, and Hans Hofmann, University of Texas at Austin. This collaborative project attempts to link behavioral differences to variation in hormone levels and brain gene expression to understand how genetic and environmental forces interact to influence evolution in suites of traits.
Predicting how genotype and environment interact to shape evolutionary processes and elucidating the mechanisms by which genetic and environmental influences produce well-adapted phenotypes are two fundamental unresolved problems in evolutionary biology that are of concern to the Sociogenomics RCN. Empirical data relating plastic and evolved differences in natural populations are quite limited, and studies examining underlying mechanisms are almost completely absent. The Kim Hoke’s lab takes advantage of the Trinidadian guppy (Poecilia reticulata) to address these questions. In her lab, Ms. Fischer uses a “Behavioral Olympiad” (including assays of courtship, aggression, escape, and open-field behaviors) to characterize adaptive variation in a suite of behaviors. Multiple hormone measurements were taken from each individual as well. She used these data to determine whether genetic and environmental forces lead to similar shifts in behavior and hormone levels, then combined behavioral and hormonal data to explore whether a shared reliance on hormonal mechanisms constrains or facilitates adaptive shifts involving multiple traits. Ms. Fischer has found that courtship, aggression, and open-field behaviors were correlated with one another, but not with escape behavior. She did not find significant differences in hormone levels based on genetic background or rearing environment; however, hormone levels influenced behavioral variation among individuals. Importantly, this relationship differed based on genetic background and rearing environment, implying that the neuroendocrine mechanisms underlying behavior are labile. Ms. Fisher will collaborate with Hans Hofmann’s lab at the University of Texas as she analyzes brain gene expression from the same individuals for which behavioral and hormone data was collected. The combination of behavioral, hormonal, and brain gene expression data will provide a powerful framework for understanding the neuromolecular mechanisms mediating genetic and environmental shifts in behavior and the role of individual variation in these processes.
In addition to advancing the science of social genomics, the experience will have important training component. Ms. Fischer notes that by spending time at the University of Texas she will have access to the genomics/transcriptomics expertise of the Hofmann lab members, who have extensive experience in this area. She will also have access to the resources available through UT’s Center for Computational Biology and Bioinformatics, of which Dr. Hofmann is the director. Her experience will enable her to bring new approaches back to the Hoke lab and other members of the CSU Biology Department. “I will be able to acquire skills that will help me more effectively and efficiently complete my dissertation” said Ms. Fischer. “Given the importance of analytic expertise in our field, advanced analytical skills will also make me more competitive applicant for postdoctoral positions.” Eva Fischer graduated with a PhD in 2015 and is now a postdoctoral reseacher at Harvard with Dr. Lauren O'Connell.