We are studying how different animal body plans have evolved on the earth. We use a combination of evolutionary and developmental studies to investigate how a single fertilized egg develops a unique morphology, depending on the spatial and temporal expression of developmental genes. The main model systems used in my lab are ascidians and hemichordates, as our major research interest is the evolution of the chordates.

One part of my lab works on the molecular phylogeny of the deuterostomes in a effort to understand the phylogenetic relationships of the different deuterostome groups. We study the phylogeny of the tunicates and hemichordates. We are interested in the relationships of species within each phyla and how the phyla are related to each other. Our best guess about the phylogeny of the deuterostomes is shown in the figure on this page.

We are studying how coloniality has evolved several times in the deuterostomes, by studying the development of colonial ascidians and hemichordates (pterobranchs). One of my students is studying the development and potential of germ cells in colonial ascidians. Other students work on the developmental mechanisms underlying development and metamorphosis. We use a variety of research tools and approaches in an effort to understand the evolution of animal body plans, particularly the chordate body plan.

Professor Billie J. Swalla is a Professor of Biology at the University of Washington and an expert in Marine Genomics. She was the first female Director of Friday Harbor Laboratories from 2012 - 2019. Professor Swalla began her career at the University of Iowa, working on cartilage and muscle differentiation and limb patterning in chicken embryos with Professor Michael Solursh.  A summer taking Embryology at the Marine Biological Laboratory in Woods Hole, MA changed her life and she moved to Postdoctoral studies with Professor William R. Jeffery at the University of Texas at Austin and Bodega Marine Lab at the University of California at Davis. Dr. Swalla worked on the molecular basis of development in tailed and tailless ascidians for Postdoctoral studies, and continued research into the evolution of chordates. Early in the 1990's she began working on molecular phylogenies of the deuterostomes and proposed a new hypothesis for a worm-like deuterostome ancestor in 2000. Molecular phylogenies led to her understanding the importance of hemichordates to understanding the evolution of chordates, and she began working on hemichordate evolution and development in 1997.  Her lab continues to work on tunicate and hemichordate phylogenies, evolution and development, and chordate origins. In 2010, she began a new project studying ctenophore evolution and development with Professor Leonid Moroz from the University of Florida. Her lab currently uses transcriptomics and genomics to investigate the evolution of animal body plans, using an Evolution and Development approach.