Welcome to the Christie Lab

Our lab uses molecular and analytical tools to answer basic and applied questions in ecology, evolution, and genetics. Most of our work is grounded in population genetics theory and we combine theory with molecular tools to address issues facing the conservation and management of wild populations. We often use fishes as our study species such that our work has direct implications for fisheries management, hatchery operations, aquaculture, and the conservation of wild fish populations. Our primary research fits into the broad theme of rapid genetic adapation. Specific research themes include: 1. rapid genetic adaptation to novel environments, 2. the evolution of resistance, and 3. the delination of populations in high gene flow systems.



Genetic adaptation to novel environments





It has recently been demonstrated that evolution can occur over short time scales - sometimes in as little as a single generation. Understanding which species and populations can rapidly adapt to novel environments - and how this process happens - has important implications for prioritizing and implementing appropriate conservation and management actions in the face of changing environmental conditions (e.g., climate change). Our lab continues to examine how species genetically adapt to novel environments such as hatcheries and the Great Lakes ecosystem.




The evolution of resistance





Sea lamprey were accidentally introduced throughout the Great Lakes with improvements to shipping canals in the 1930s. Sea lamprey are parasitic; the adults attach to and feed on large-bodied native prey fishes such as lake trout. This parasitic lifestyle coupled with no previous history of coevolution with native species led to large population reductions in parasatized native fishes. Consequently, a lampricide known as 3-trifluromethyl-4-nitrophenol has been used since the 1950s to greatly reduce lamprey abundance throughout the Great Lakes. No other lampricide is currently used and thus our lab is focusing on whether resistance to this chemical is beging to emerge after > 60 years of application.




Deliniating populations in high gene flow systems





Identifying the spatial and temporal boundaries of fish populations is critical for effective fisheries management and conservation. However, the delimitation of fish populations can be challenging because many species are difficult to observe directly in their aquatic environments. Furthermore, fish populations are often connected by dispersal that occurs during a relatively cryptic pelagic larval stage as most fish larvae are miniscule (~1-3mm) and nearly transparent, making them difficult to observe directly. This pelagic larval stage is ubiquitous; many freshwater fishes and over 95% of all marine fishes have a pelagic larval stage as part of their life histories. Being pelagic, currents can transport larvae to populations that are hundreds of kilometers away from where they were spawned. On the other hand, behavioral adaptations, homing mechanisms, and a complex interplay of biophysical processes can result in larvae returning to the same population from where they were spawned. Thus, given the challenges associated with tracking miniscule larvae and the observation that larvae can travel highly variable distances, our lab uses novel, integrative approaches in order toto elucidate the degree to which fish populations are connected.