The branching coral Stylophora pistillata: Contribution of genetics in shaping colony landscape

Colony architecture in branching colonial organisms is established through iterated processes of the structural units (modules), both zooids and the branches. Different approaches to analyzing colonial organization have revealed an intrinsic order to branched forms. By using mathematical models such as fractals, simulations of diffusion and flow, applying tree architectural models and developmental canalization ideas or analyzing heterochrony, attempts have been made to mimic the rules of colony formation. However, most approaches have not prioritized the rationale that structures and rules which govern the way a branching organism is built are heritable characteristics, and that even phenotypic plasticity is the expressed outcome of plasticity genes. There is no model system yet for the study of genetic impact on the architecture of branching modular organisms. Stylophora pistillata, an Indo-Pacific hermatypic coral, is treated here as such a model. S. pistillata morphometric characters are then analyzed. I raise the possibility that genetics is a key factor in shaping colony landscape and that genetic factors should be considered when studying the architecture of marine branching forms.