Research: Evolutionary Genetics
Comparative genomics; Phylogenetics; Phylogeography; Population biology
I joined the Department of Biology during August 2011 after completing a postdoctoral fellowship at the University of California, Davis with David Neale and Charles Langley. My graduate work was completed at the University of Washington in the Department of Botany (now Biology), while my undergraduate degree was obtained from Humboldt State University.
I am an evolutionary geneticist whose research focuses around the following three major themes: (1) Adaptation within and among natural tree populations How do woody plants adapt to their environments? What are the genes that facilitate this process? How are these genes organized within the genomes of woody plants? I try to answer these questions using a variety of approaches ranging from population genetic surveys of natural populations to association genetic dissection of complex phenotypes. The unifying theme underlying all of these approaches is the discovery of the genetic basis of adaptive plant phenotypes. (2) Development of methods to infer patterns of natural selection from genome-wide SNP data Standing patterns of genetic diversity result from the interplay of several population genetic processes, such as natural selection, genetic drift and migration. When methods developed to identify these processes are used in a hypothesis-testing framework, however, they do not often exhaustively divide the sample space into mutually incompatible outcomes. Thus, rejection of one hypothesis, a null hypothesis for example, does not necessarily imply that the alternative is true or even likely. The reason is that several different processes can individually, as well as jointly, result in the same patterns. It is prudent, therefore, to utilize a range of methods that each examines different aspects of the standing patterns of genetic diversity. I am currently examining several different methods for their performance in simulations that mimic natural plant populations. (3) Phylogeography of North American woody plants The woody plant flora of North America is composed of a fascinating diversity of species. I use a variety of phylogeographic, biogeographic and phylogenetic approaches with which to understand the origin and diversification of species comprising this flora. These approaches tend to be hypothesis driven where multiple competing hypotheses are proposed and the best one(s) is/are chosen using some form of statistical model selection. This is also important because divergence history confounds the ability to identify adaptive genetic variants.