I am an evolutionary biologist studying the phylogenetic history of plants. My earliest work was with Coreopsis (Asteraceae), but most of my research has focused on the wheat tribe, Triticeae, a group of about 350 species in the grass family, Poaceae. I am especially interested in the complex reticulate patterns that arise when distinct lineages undergo gene exchange. The grass family includes many examples of reticulate evolution, involving hybridization and allopolyploidy.
Phylogenetic analyses of the Triticeae reveal a history of reticulation among diploids and polyploids. Early molecular studies based on comparisons among individual gene trees showed phylogenetic conflict among molecular data sets, even when only diploids were included. Currently we are applying targeted sequence capture of low-copy protein-coding loci to a broad sample of diploid taxa to determine whether conflicting phylogenetic signal is localized the genome, or broadly distributed throughout.
The wheat tribe includes many examples of allopolyploidy. The St genome of Pseudoroegneria seems especially inclined to join other genomes in a variety of allopolyploid combinations. Elymus is an entirely allopolyploid genus, comprising several different combinations of parental genome donors, but they all share at least one set of Pseudoroegneria (bluebunch wheatgrass) genomes, which are designated St. We have applied phylogenetic methods to uncover the history and diversity of allotetraploids and allohexaploids within the tribe.
Graduate students in our lab have studied phylogenetics and population biology in a broad range of taxa, through collaborative advising with local researchers. See People for more information.