Connecting genes and social behavior in a unique animal model

Emory University, Atlanta GA

Investigators

Abstract

Research on the genetic basis of social behavior has proceeded slowly because of a general lack of interdisciplinary expertise in both genomics and behavior. This project is a collaboration between a PI trained in molecular biology and genetics and a co-PI trained in the analysis of social behavior and its hormonal mechanisms. New high-throughput sequencing methods enable the detailed study of the genetic basis of social behavior in a variety of carefully chosen species, even in the absence of a completely sequenced genome. A songbird model, the white-throated sparrow, is used to characterize genes involved in aggression. This species exhibits a plumage polymorphism that correlates with many aspects of social behavior. Individuals with a white stripe (WS) on the crown are more aggressive and have higher song rates than individuals with a tan stripe (TS). The plumage polymorphism is linked to a chromosomal rearrangement, presenting a unique opportunity to study the relationship between genes and social behavior. This project uses the powerful and exciting technology of next-generation sequencing to identify genes in the brain that vary in expression with relation to both plumage morph and aggressive behavior. Once identified, the expressions of these genes are mapped in the brain to help clarify their role in behavior. Gene sequences are analyzed to identify variation in protein sequence that is linked to plumage morph. These results provide extensive information on the expression, sequence, and distribution of genes linked to aggression. Intellectual Merit: Genome-wide association studies have identified a vast array of single nucleotide polymorphisms that are weakly associated with phenotypes but which explain very little variation. The link between genetic polymorphisms and behavioral constructs such as "aggression" is still lacking, largely because of a failure to consider the intermediary steps that happen at the levels of gene transcription and protein function. Progress in this field will require an understanding not only of whether gene sequences contribute to behavior, but how they do so. The behavioral sciences would thus benefit from the expertise of researchers trained to address these questions. In this project, a PI with a background in molecular biology joins a psychology department and integrates genomics techniques and resources into the study of social behavior. It is essential that studies intended to elucidate the mechanisms driving social behavior be conducted in a way that allows animals to interact in their natural environment. Behavioral studies on laboratory-housed animals often do not represent naturalistic conditions, and can produce results that are not biologically relevant. This study links genes and social behavior using animals that are observed and collected in their natural habitat. Although social behavior is complex and predicted to involve many genes, only a few genes have been definitively linked to social behavior. These results greatly contribute to our knowledge base of gene expression in the brains songbirds, an important model useful for studying the relationship between genes and behavior. Broader Impacts: The PI develops and teaches a course, aimed at psychology graduate students interested in genetics-based approaches, which emphasizes basic gene function, the use of genomics databases, and the interpretation of associations between polymorphisms and behavior. Ultimately the course encourages psychology students to integrate genetic approaches in to their research in a powerful way. The PI's other activities include mentoring undergraduates, making presentations at underserved K-12 schools, and mentoring high school students and teachers from underrepresented groups.