MCA: Genomic diversification and speciation along ecological gradients in a marine fish radiation

Understanding the formation of new species in the marine environment has proven to be a challenging task for evolutionary biologists. The potential for high levels of migration and the apparent lack of geographical barriers create a scenario where ecological diversification and life history shifts are likely important in the speciation process. This research program will determine the genomic basis of divergence among closely related species and populations along latitudinal and depth gradients to determine the role of adaptation in the speciation process.

Rockfish (Sebastes) are an ideal system to examine these questions as they are a diverse group of temperate fishes inhabiting a wide array of habitats, and they have been subject to numerous phylogenetic studies. This study will build upon a growing set of studies aimed at better understanding the speciation process in the marine environment. Training opportunities will be provided to undergraduate and graduate students at Cal State LA, and data from this project will also serve as a resource for the management of rockfish, many of which are commercially important.

This project will utilize genome scans and de novo genome assemblies to test for speciation histories of rockfish associated with divergence along ecological (depth) or geographic (latitude) gradients. These findings can be used to better understand the role of natural selection on the genome and how this contributes to the diversification of this group.

The first aspect of the study will examine the role that ecological adaptation along a depth gradient has played in the formation of new species. The second aspect will contrast these findings with latitudinal divergence among closely related species. Together these results will provide novel insights into the speciation history and genomic divergence for closely related marine species, and provide a framework for understanding the relative roles of selection and genetic drift on generating and maintaining marine diversity.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.