|Professor, Ecology and Evolutionary Biology|
Evolution/Development of Invertebrate Body Plans, Paleobiology and Marine Speciation Our laboratory brings an evolutionary perspective to the study of developmental genetics. In particular, we are investigating the role played by developmental genes in the early, geologically rapid Cambrian evolution of animal morphology. Comparison of developmental gene expression between morphologically distinct kinds of organisms is the primary focus in the laboratory. To this end, we have retrieved the engrailed gene via PCR from all the major classes of molluscs. We are now in the process of comparing the expression pattern of this gene through in situ hybridization studies in clams, snails, and chitons. In addition, we are reconstructing histories of gene duplication events using phylogenetic methods. The phylogenies produced permit a better understanding of the evolution of the genes, as well as shed light on the sequence of events in the evolution of animal development. Evolutionary hypotheses generated by examination of these developmental gene trees are then tested against the fossil and phylogenetic record of animal evolution. Gene sequences are also useful in reconstructing the relationships between organisms. We are especially motivated to explore such branching histories of organisms when they relate to paleontology, historical aspects of marine biology or climatic process. For example, a new project in the lab involves the use of molecular markers to study gene flow associated with the transport of planktonic larvae in marine organisms. Another molecular study investigates the geologic and climatic isolation of populations of jellyfish in salt water lakes, separated from the sea. In the lab we have ongoing interests in several non-molecular questions in invertebrate paleontology and paleoclimatology. Previous studies have explored the functional morphology of fossil cephalopods. Other studies pertain to the effects of milankovitch-driven climate change on sea level in non-glacial times, mans ongoing contribution to sea-level change, and climatic influences on the evolution of wetland faunas.