Gene flow, adaptation, & fitness
I am testing how gene flow from an adaptively divergent population affects fitness in wild populations of Trinidadian guppies. I conducted an intensive monthly mark-recapture survey of guppy populations in two streams before and several generations after the onset of gene flow from divergent guppies that were introduced upstream.
Gene flow can reduce fitness by introducing maladaptive alleles and breaking down local adaptation. On the other hand, the infusion of new genetic variation can benefit populations, especially if they are small and inbred.
This project integrates demography, pedigree reconstruction, and common garden assays to determine the mechanisms by which gene flow positively and/or negatively impacts fitness.
This project is part of an NSF funded study in collaboration with Chris Funk, Lisa Angeloni, and other members of the CSU guppy group.
Guppies in the CSU news!
Genetic rescue across the genome
Uncovering genomic patterns during initial contact and subsequent introgression between adaptively divergent populations is a first step towards a mechanistic understanding of the genomic effects of gene flow on fitness and adaptation, a question that is increasingly crucial for the conservation of biodiversity in light of human-mediated gene flow.
Using the guppy populations described above I am implementing a RAD-seq approach to understand differential responses of loci across the genome when gene flow, selection, outbreeding depression, and genetic rescue are on-going.
Landscape & conservation genetics
Landscape genetics provides a powerful framework to test anthropogenic effects on spatial structuring of genetic diversity, such as identifying barriers to gene flow, connectivity corridors, and evaluating stocking success.
I apply these techniques to species and habitats of conservation concern. I work with the Colorado Division of Parks & Wildlife to determine connectivity patterns in the Arkansas darter, a state-threatened species that is a candidate for listing under the US Endangered Species Act.
I also collaborate with Jeanne Robertson (Cal State Northridge), Lauren Chan (Claremont McKenna College), and Betsie Rothermel (Archbold Biological Station) to study the effects of fire on diversity patterns of the Pine Woods treefrog across imperiled Florida Scrub habitat. Understanding the effects of fire on genetic diversity and connectivity of Florida Scrub amphibians is crucial for their conservation in this endangered ecosystem.
Guppy gut microbiome
In collaboration with microbial ecologist, Sarah Evans (Kellogg Biological Station), and freshwater ecologist Eugenia Zandoná (Rio de Janeiro State University), we are studying the diet and gut microbiome across populations of Trinidadian guppies with different evolutionary histories. This project will help distinguish the relative roles of environment and genetic determinants that structure microbial communities in vertebrate hosts.