Project Summary/Abstract: The degree to which behavioral variation is shaped by experiences or determined by heritability has long captivated biologists and non-biologists alike. It is now clear that behavior often has a genetic component, but mapping specific genetic variants underlying differences in behavior remains a major challenge. Recent advances in “-omics” technologies and analytical tools provide an exciting opportunity to uncover connections between genetic and behavioral variation. Parental care is a complex behavioral trait that has independently evolved many times across the animal kingdom. The neural, physiological, and molecular mechanisms of maternal (female-provided) care have been widely studied and appear to be highly conserved across deep evolutionary time. Yet, there remains a critical gap in our understanding of the mechanisms of paternal (male-provided) care. The small stream fishes commonly called darters provide a unique opportunity to investigate the genetic and evolutionary drivers of paternal care. Darters comprise the most diverse group of vertebrates in North America and exhibit ample variation in reproductive behavior. Paternal care has evolved repeatedly among evolutionarily independent darter lineages and has also been secondarily lost in at least one species. Our goal over this five-year project is to use the darter system we developed to study the biological basis of evolved differences in paternal care. We will leverage natural replication in this system to test the hypothesis that similar genetic and molecular changes underlie the evolution of this behavior in darters. Our lab has pioneered the development of genomic resources and functional genetic tools for darters, which will serve as a platform for the proposed work. First, we will take advantage of the fact that closely related darter species with and without paternal care can form viable crosses to produce fine-scale genetic maps for paternal care behavior. Second, will use our previously developed bioinformatic pipelines to conduct genome scans for selection and identify genes repeatedly under positive selection only in species that have evolved paternal care. Additionally, we will ask whether these same genes show signatures of relaxed selection in a species that secondarily lost paternal care. Third, we will investigate the neural and transcriptional basis of paternal care using an approach for molecular profiling of behaviorally relevant neurons that we recently developed in darters. The proposed work will be complimentary to other lines of research in the lab aimed at applying population genomic, quantitative genetic, and functional genetic methods in darters and other fish models to test fundamental evolutionary hypotheses and uncover genotype-phenotype connections. This innovative project will bridge behavioral neuroscience and evolutionary genomics – fields which have historically remained largely siloed and limited to model systems – to investi...