Genetic adaptation to new environments can happen rapidly. The mechanisms behind this accelerated adaptation, however, are only beginning to be understood. Identifying the specific genes that respond to selection in novel environments can provide us with a greater understanding of how rapid adaptation occurs. Species introductions provide an excellent study system to understand this process.
We are using the introduction of Chinook Salmon in New Zealand to better understand the process of rapid adaptation and diversification of life history traits. In the 1870s, Chinook Salmon were introduced into the Hakatramea river in New Zealand from source populations originating in the Central Valley (CV) of California. Since that time, Chinook have populated many rivers throughout New Zealand, developing life history traits independent of the original introduced population. This rapid evolution of new traits is not well understood, and the genetic basis even less so.
Using whole genome resequencing on samples from both the Central Valley of California and throughout New Zealand, we are addressing the following questions:
- What is the source population for the New Zealand introduction?
- What regions of the genome have been selected upon in the introduction?
- Is there evidence for local adaptation among the introduced populations and how might this shed light on the process of run timing diversification?
This information will help us better understand the process of rapid adaptation, as well as help understand the evolution of life history trait diversification.