Ian J. Wang

Molecular Evolution Postdoctoral Fellow
Center for Conservation & Evolutionary Genetics, Smithsonian Institution

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A central goal of evolutionary biology is to understand the origin and maintenance of genetic and phenotypic variation in natural populations. My research program focuses on utilizing landscape genetic and phylogenetic frameworks to investigate the relationships between environmental, geographic, morphological, and genetic variation in natural populations. A theme through all of my work is the integration of diverse forms of data and computational analyses to address fundamental questions in evolution and ecology. My previous research has utilized a wide variety of scientific techniques, including phylogenetics, population genetics, spectral reflectance analysis, toxicity assays, and GIS methods, and has been conducted in a diverse set of ecosystems, including deserts, alpine meadows, and temperate and tropical forests.

Landscape Genetics...
Ecological and geographic variables can affect spatial genetic structure by contributing to geographic isolation, in which landscape barriers and geographic distances cause restricted gene flow, and ecological isolation, in which gene flow among populations inhabiting different ecological environments is limited by selection against dispersers moving between them or by individual preference to remain in a particular environment. While landscape genetic methods have been developed to study geographic isolation in detail, ecological isolation has received much less attention. I am currently developing a structural equation modeling framework to quantify the effects of geographic and ecological isolations and applying it to a comparative analysis of 17 species of Anolis lizards. Each of the 17 Anolis species has substantial intraspecific genetic variation and inhabits a Caribbean island with considerable environmental heterogeneity, providing excellent opportunities to study the roles of geography and ecology in population genetic divergence.

Ecological Genomics...
Although it is well known that environmental differences can shape patterns of genetic and phenotypic variation, few studies have connected environmental variation to genetic adaptations. I am currently investigating the genes underlying local adaptation in a major pathogen, Batrachochytrium dendrobatidis (Bd), which is partly responsible for widespread amphibian declines. Using genomic data and new spatial analysis methods, we can integrate genetic and environmental data to identify candidate genes for adaptation to particular environmental conditions. The identification of genes carrying a signature of selection under this method is especially valuable because it directly links the genes under selection to specific environmental forces of selection

Phenotypic Evolution...
I'm fascinated by patterns of phenotypic variation, especially color polymorphism in aposematic species, because aposematic traits are traditionally predicted to be heavily constrained. Several species of poison-dart frogs display remarkable levels of color variation, and investigating the evolution of phenotypic polymorphism in these species can tell us a lot about the forces promoting biological diversification in nature. I've used a variety of approaches to test hypotheses about the evolution of color polymorphism in poison-dart frogs, including landscape genetics and phylogeography, toxicity and spectral reflectance analyses, and chemical profiling of skin toxins.