Meeting Abstract
The genetic mechanisms that contribute to adaptation and speciation are not completely understood, especially within marine ecosystems. These evolutionary processes can be elucidated by directing attention to adaptive radiations, because they provide replicates of divergence within a given environment or time-frame. Marine rockfishes (genus Sebastes) are an exemplary demonstration of adaptive radiations and unique model system for studying adaptive evolution, because of the extensive diversity found within this group which include morphology, ecology, and a broad range of life spans. Brain transcriptomes were sequenced via RNA-Seq from three species within the subgenus Pteropodus (S. carnatus, S. nebulosus, and S. maliger) and a pair of related congeners to Pteropodus in order to find repeated patterns of adaptive evolution. De novo assemblies from these transcriptomes were used to identify 3,867 orthologous clusters, and 866 genes were subject to positive selection based on site models. Genes under positive selection belonged to a variety of gene functions that include sensory perception, growth, and metabolism. By using branch-site models, we found 686 genes subject to positive selection that were restricted to Pteropodus in comparison to closely related congeners. Genes under positive selection within Pteropodus were associated with visual perception, regulation of cell proliferation, and response to stimulus. These candidate genes will provide a better understanding of how this subgenus radiated and adapted to their respective habitats within the Northeast Pacific, and as more genetic patterns are identified with multiple species within Sebastes, we can make stronger inferences about adaptation and speciation.
