De novo assemblies, annotations, and gene expression profiling of gill epithelium from 16 species of Fundulus killifish in response to salinity change.
Ion and Acid-Base Regulation in Fish Symposium
13th International Congress on the Biology of Fish
Calgary, Alberta, July 15-19, 2018
Estuaries are characterized by periodic fluxes in salinity. Many species of North American killifish (Fundulus) are estuarine specialists and harbor euryhaline phenotypes. Three clades within Fundulus independently radiated into freshwater environments and have lost their abilities to tolerate high salinity. We use Fundulus as a comparative model system for studying the physiological and genetic mechanisms that diverge between euryhaline and freshwater species. We examined 16 estuarine and freshwater species with representation from each of three clades. Fish from all species were acclimated to either brackish or fresh water then exposed to an acute brackish water challenge. Gill transcriptome data were collected. To enable multi-species comparisons, reference transcriptome assemblies were generated de novo for each species then used to analyze transcriptional responses to salinity change by clade and physiology. We find differences in the gene expression between euryhaline and freshwater species, some of which are shared across clades, implicating molecular mechanisms that contribute to divergent osmoregulatory physiologies.