Meeting Abstract
Despite obvious whole animal, tissue level, and biochemical differences among species with different diets, dietary specialization has molecular underpinnings that are not well understood. In this project, we used comparative transcriptomics of pancreatic and intestinal tissues to observe how prickleback fishes (Stichaeidae) achieve dietary-driven differences in gut size and function. With dietary variation among sympatric species, sister taxa with different diets, and convergent evolution of herbivory, the Stichaeidae is an appropriate system in which to study the genetic underpinnings of dietary specialization. Cebidichthys violaceus (herbivore), Xiphister mucosus (herbivore), X. atropurpureus (omnivore), and the carnivorous Anoplarchus purpurescens were captured during a single low-tide series on the central California coast. Using the Illumina platform, transcriptomes were sequenced for the two tissues from two individuals per species, and genome-driven assemblies were performed using the C. violaceus genome as the reference. Analyses are underway, but we will present data on differential expression, and enrichment of genes involved in digestion and absorption of nutrients. We have previously observed differences in gut size and function in these species, and recently reported gene copy number variation for the digestive enzyme amylase, which partially explains variation in biochemical activity levels of this enzyme in these same species. This broader transcriptomic analysis will allow us to extend our coverage beyond a single digestive enzyme gene to the multitude of digestive and absorptive processes, and will provide insight into how vertebrates specialize to use specific resources.
