Our research spans a wide range of topics in plant systematics and evolution, involving undergraduate and graduate students as well as international collaborations. Our general research goal is to test systematic and evolutionary hypotheses in a phylogenetic context. We integrate information from DNA sequences, morphology, and fossils to reconstruct the phylogeny of plants and use the phylogeny as a basis to elucidate the biogeographic history (e.g., time and place of origin, time and routes of migration) and to understand the rate and pattern of molecular and morphological evolution. We apply molecular population genetics and phylogeographic methods to study evolutionary pattern and dynamics in rare and endangered species, in natural hybrid zones, and polyploid species. We have recently expanded our research to evolutonary developmental genetic study and use biotechnology and comparative genomic approach to understand the molecular and developmental basis of important morphological changes in plant reproductive structures.

1. Phylogenetic and biogeographic studies - integration of morphology, molecules, and fossils -supported by NSF

2. Evolutionary developmental genetics - towards unraveling the molecular basis of inflorescence architecture divergence among dogwood species - currently supported by NSF

  •      Molecular evolution– gene duplication, rate and pattern of sequence
        evolution of candidate genes in relation to morphology

  •      Comparative developmental study of inflorescences

  •      Developing a transformation system in dogwoods for testing phenotypic
        effects of candidate genes

  •      Comparative gene expression

3. Population genetics, phylogeography, and conservation genetics -currently supported by DOD

  •      The flowering dogwood Cornus florida.
  •      Conservation genetics of the federally endangered species Echinacea   
         laevigata     - supported by Nature Conservancy
  •      Phylogeographic study of Nyssa sylvatica complex – implication in
        species delimitation and post-glacial evolution.

  •      Population structure and testing contrasting hypotheses on the origin
        and maintenance of a broad natural hybrid zone in the buckeye genus
            Aesculus.

4. Polyploid speciation and molecular evolution after genome duplication in the dwarf dogwoods