Scott A. Hodges
Professor, Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, CA 93106
The primary motivation of the research in the Hodges laboratory is to understand how biological diversity is generated, by focusing on identifying the genetic basis of adaptations and speciation. We identify broad evolutionary patterns through phylogenetic analyses and then test the inferred processes that produce these patterns through studies of populations. Ultimately, we aim to identify the genes and mutations underlying specific adaptations, particularly those that confer reproductive isolation. To this end, in collaboration with multiple laboratories we have worked to develop Aquilegia as an emerging model system through the establishment of an EST database, physical and genetic maps, and whole-genome sequencing.
We have identified a broad pattern of increased species diversity in plant taxa that have evolved floral nectar spurs (e.g., Kay et al. 2006). From this pattern we have inferred that modification of nectar spurs allows greater specialization to different pollinators, which in turn leads to reproductive isolation and speciation. We have tested these ideas in the columbine genus Aquilegia and shown that specific floral traits such as spur length, color and orientation affect pollinator visitation or pollen dispersal. Recently, the Hodges laboratory has focused on the evolution of specific floral traits, particularly nectar spur length and floral color (e.g., Whittall et al. 2006; Whittall & Hodges 2007; Hodges & Derieg 2009). For flower color, we have determined that convergent shifts to light-colored flowers are likely caused by convergent changes to transcription factors (Whittall et al. 2006). Furthermore, we have now identified a full set of genes controlling the broad pathway involved with anthocyanin pigment production (Hodges & Derieg 2009).
The proposed RCN will be extremely important for training future young scientists in our laboratory. The broad nature of the questions we are addressing means that students need to utilize a broad range of techniques, certainly not all available in our laboratory. For instance, we have studied gene expression in specific tissues, but future studies would benefit from more specific localization through in situ hybridization. As we identify candidate genes, we need to utilize RNAi techniques or stable transformation to validate their function. Students will directly benefit from the RCN by learning or adapting these techniques from other laboratories. Next-generation sequencing is now making both transcriptome and genomic analysis possible at the population level, and we would be able to assist other laboratories in analysis and techniques of such datasets. Finally, our laboratory is particularly well versed in studying ecological interactions in the field, where many of the specific questions in evo-devo-eco are developed and adaptations verified. We look forward to assisting others developing best practices and consistent methods to allow cross-laboratory comparisons for these field-based studies.