The evolution of morphological diversity of bilateral animals is one of the important issues of biology. Bilateral animals (bilaterians) consist of three major superphyla: Deuterostomia (for example, vertebrates, ascidians, and echinoderms), Ecdysozoa (for example, arthropods and nematodes), and Lophotrochozoa (for example, annelids and mollusks). To understand the evolution of the bilateral animal body plan, it is important to compare the developmental mechanisms of these groups.
When I was an undergraduate student, I was excited to learn the molecular and cellular basis for beautiful pattern formation of embryos and I decided to learn more. During the graduate school and postdoctoral work, I studied the embryonic development of the oligochaete annelid Tubifex, the gastropod mollusk Ilyanassa, and the flour beetle Tribolium. Their body plans are very different; however, they share some aspects of early developmental processes such as cell lineages, cleavage patterns, and segmentation. These similarities and differences provide us with interesting insights into the evolution of the animal body plan. My current major project is to study the cell polarity and morphogenesis of embryos of the ascidian Halocynthia roretzi. Ascidians belong to the sister group of the vertebrates. Therefore it is expected that ascidian research will also help our understanding of vertebrate evolution.