Catherine Peichel - US grants

A fundamental puzzle in evolutionary biology is whether evolution is repeatable: if many identical starting populations were exposed to the same type of novel environment, would they all evolve the same adaptations? Would the adaptations result from changes in the same underlying genes? This research project aims to answer both questions using a small fish, the threespine stickleback, as a study subject. The same ocean-dwelling form of stickleback colonized many separate river basins when the glaciers melted ~12,000 years ago, providing a naturally occurring experiment to test the repeatability of evolution. The researchers will measure environmental, morphological, and genetic divergence between adjacent lake and stream populations of stickleback, from each of 16 watersheds that represent separate instances of evolved lake-stream differences. They will then apply state-of-the-art statistical analyses to measure the extent to which differences between lake and stream types have evolved repeatedly or are unique to each watershed. Genetic analysis will reveal the extent to which repeated morphological differences result from evolutionary changes in the same genes.

The project will reveal general principles of how predictable evolutionary change is, and pioneer relevant statistical methods. Such principles and methods are vital to anticipating how pests or diseases may evolve in response to pesticides or drugs, or how species will adapt to climate change. In addition, the project will pair up leading biological researchers with high-school biology teachers and pre-service teachers-in-training, giving K-12 science teachers practical research experience involving fundamental principles of evolutionary biology.

A longstanding challenge in behavioral research has been to identify the internal factors that bring about differences in behavior between individuals or species. Despite the importance of this goal, there is a paucity of information about the genetic and neural mechanisms that underlie the dramatic differences in behavior observed within and among species in the wild. This project seeks to identify the mechanisms that underlie divergence in social behaviors, using schooling behavior in stickleback fish as a model system. Sticklebacks are an emerging genetic model system with numerous populations that differ in behavior, making them ideally suited to this work. Sticklebacks from marine and freshwater environments exhibit striking differences in schooling behavior. A combination of modern genetic and neurobiological approaches will be used to dissect the genes and neural circuits that underlie differences in schooling behavior between stickleback populations.

This work has the potential to yield one of only a few known "behavior genes" in any system and one of the first genes that shape behavioral differences between divergent populations of animals in the wild. In addition, this work seeks to link genetic variation to variation in the nervous system, thereby providing important insight into the process of behavioral divergence.

This project will provide opportunities for undergraduate students to gain experience in cutting- edge genetic analysis. In addition, a collaboration has been established with a Seattle-area high school serving a diverse community of students. These students will participate in the analysis of the behavioral and genetic data from this project, providing them with a unique opportunity for engagement in the scientific process.