Sustaining Genetic Variation After Population Bottlenecks
Populations that undergo sharp declines in size (population bottlenecks) are expected to lose genetic variation and adaptive potential. However, there are a variety of mechanisms by which a population can sustain sufficient genetic diversity levels, including gene flow between divergent populations, increasing propagule size of the post-bottleneck population, as well as the underlying genetic architecture of traits and the surrounding selective landscape that affects them. For this avenue of research, I build off of theoretical models to explore the parameters influencing increases in genetic variance after population bottlenecks, and connect the predictions of the theoretical models to empirical systems.
Genetic, Environmental and Spatial Contexts of Biological Invasions
|
Biological invasions offer excellent natural "experiments" to evaluate the evolutionary and ecological patterns that lead to establishment in spread. I, along with a team of dedicated undergraduates, use a combination of physiological, spatial and genetic tools to better understand the historic contexts of invasions, with a particular focus on invasive anurans in Florida and the Caribbean. With these data, we have been able to reconstruct the historic introductions and spread of invasive anurans in this region, as well as determine environmental characteristics that may have promoted or impeded their establishment.
|
Maintaining Genomic Variation in Systems with Strong Sexual Selection
While the impact of various factors, such as population bottlenecks, habitat fragmentation and gene flow, on genomic diversity are well understood, there are many times in which it is poorly understood how population naturally maintain variation. Specifically, species that face intense sexual selection are theoretically expected to harbor low genetic variation, yet populations still persist and adapt. Under this framework, I am interested in how lekking species, whereby a small subset of males dominate mating grounds, maintain sufficient genetic variation despite the expectation that variation would erode over time (The Lek Paradox). I use a large set of genomic and phenotypic data on prairie chickens (Tympanuchus) to test various theoretical hypotheses that have been used to explain The Lek Paradox.
Cryptic Variation in Understudied Species Groups
|
Tools like genomics and spatial modelling can be a powerful way to study cryptic aspects of diversity. Such cryptic aspects include speciation, population variation and dispersal in organisms that are naturally difficult to study. I use a multitude of tools, with a primary emphasis on genomics, to provide descriptive accounts of species and population-level diversity, with a current focus on neo-tropical insects. I am currently working in the genus Corethrella, or frog-biting midges, where I am using genomics to uncover the potential selective mechanisms behind divergence in species complexes. I have also worked on similar descriptive analyses on neo-tropical fungus-farming ants and their social parasites, where I used ddRAD and microsatellite markers to describe patterns of population structure and dispersal.
|