Grant: Discovery Launch Supplement

Hybridization, when closely related species breed with each other, is increasing due to human impacts. Human disturbance is expected to result in more opportunities for mating between previously separated species, but it is difficult to predict whether this increased potential will actually translate to more hybridization. Many outcomes are possible: the two species can remain separate, there can be rare hybrids with most individuals still breeding within their own species, or hybrids can be very common. In fact, hybridization between the same two species can even differ dramatically from place to place. This variability is puzzling given the prediction that hybrid fitness (an individual's survival and reproduction) is primarily controlled by genetic incompatibilities that  that are not thought to vary across locations. this is inconsistent with what has been found when looking at the genetics of within species fitness, where it is clear there are large environmental effects. The long term goal of my research is to understand and predict how the environment affects rates of hybridization, given that environments and genes can interact. My first short term goal is to develop expectations for outcomes of hybridization when genetics and the environment interact to form hybrid fitness. Simulations are useful because I can control the underlying processes, such as the strength of genetic effects and the influence of the environment on hybrid fitness. By simulating genomes from known scenarios, I assess how well my statistical methods detect genetics vs environment from the number and fitness of hybrids. From this, I develop specific expectations of how different processes should look in wild systems. My second short term goal is to use wild mice as a model to understand to what extent the environment interacts with genetics to affect hybrid fitness. I will use deer mice species to look at hybridization across Ontario. By sequencing the genomes of 1000's of mice from where the two species ranges met, I will be able to tell how much the environment affects the rate of hybridization. Further, I am part of a long term study of mice, where we will ask how rates of hybridization have changed over time. Between these two studies, I will cross-validate my findings. By comparing empirical patterns to expectations developed from simulations, I will address how species boundaries are maintained across changing environments when there is hybridization. My research is significant because hybridization is an important evolutionary process that can both increase and decrease biodiversity, and hybridization is increasing in Canada. An understanding of hybridization affects conservation biology, policy, and species management. Additionally, my proposed project will train 4 graduate and 5 undergraduate students across these axes. The skills that HQP learn in my lab will directly translate into careers in academia, government, NGOs and industry.