Christopher J. Lowe
My research interests are in the field of evolution and development, and more specifically the evolution of the deuterostomes. This major metazoan lineage is made up of four major groups; chordates, echinoderms, hemichordates, and Xenoturbellida . The early evolutionary history of the deuterostomes remains poorly understood and surprisingly even the evolutionary origins of our own phylum, the chordates, remains a major puzzle for zoologists. This uncertainty is partly due to a poor early fossil record for this lineage, but also due to the enormous morphological disparity in adult body plans between the major groups. Reconstructing the body plan of a plausible common ancestor based on extant forms is fraught with difficulties. My work attempts to make some headway in this area, and has focused on investigating the role of developmental genes that underlie these divergent body plans and morphologies in hemichordates and echinoderms. By comparing the expression and roles of these genes to their orthologues in chordates I am trying to gain insights into early events in deuterostome evolution.
We have largely focused on the origins and early evolution of the vertebrate brain and central nervous system. While the brain is clearly a key innovation of our phylum, we understand very little about its evolutionary origins outside of the chordates. Much progress has been made in identifying the early molecular genetic program of brain patterning and morphogenesis in vertebrate model systems. However, gene interactions in vertebrate central nervous system development are themselves very complex: widespread duplication and expansion of developmental regulatory gene families have led to functional redundancy, making functional studies sometimes difficult to interpret. We have been developing the hemichordate Saccoglossus kowalevskii as a less complex developmental model for addressing early evolution and origins of the vertebrate nervous system. As a phylum closely related to chordates, hemichordates are the most promising group for addressing issues of chordate brain evolution and development. Unlike chordates, their nervous system is organized on the basis of a nerve net rather than a centralized structure. We have been investigating conserved gene regulatory networks involved in the regionalization of the vertebrate brain during hemichordate development and find a remarkable conservation of gene expression, despite the organizational disparity between the nervous systems of both groups. I plan to establish the earliest, and most fundamental aspects of the molecular genetic networks that were involved in early brain evolution. This approach should not only help elucidate the early patterning events leading to chordate brain evolution, but also be generally informative about how conserved regulatory networks can generate such amazing neuroanatomical diversity during animal evolution.