For my PhD, I am exploring patterns and predictability of adaptation in threespine stickleback (Gasterosteus aculeatus). Using a large-scale field experiment in Alaska, I am tracking the evolutionary trajectories of these populations following colonization of a new environment across multiple levels: from population dynamics, to phenotypic changes, to the underlying genetics.
In 2019, we colonized nine fishless lakes in the Kenai Peninsula of Alaska with stickleback from a pool of nearby populations. These lakes were treated with Rotenone in 2018 to get rid of invasive northern pike which had ravaged the local fish populations. In collaboration with the Alaska Department of Fish and Game, we introduced threespine stickleback into these lakes, a native species of ecological importance. These introductions provide the perfect opportunity to watch the process of adaptation in real-time.
On the level of population dynamics, I am exploring the factors that determine the success of a source population once exposed to a new environment. Primarily, I will be testing if increased similarity between your old and new environment makes you more likely to survive and thrive.
Also on the population level, I am taking this opportunity to explore the potential for progress towards ecological speciation between these two ecotypes and among these divergent populations. I'll be doing this by looking at patterns of mating and admixture when multiple populations are introducted to the same lake.
On the phenotypic level, I am tracking how the morphology of fish within these populations is changing over time. As well, I am seeing how parallel these changes are among populations and if the environment of the lake can predict the direction and magnitude of phenotypic response.
On the genomic level, I am determining the genetic basis of the observed morphological variation and changes. I will explore the genes that are associated with morphology and determine if the same genes are always associated with the same morphological changes. This work addresses the complex genetic basis of adaptation.