Mechanism and Evolution of a Stolen Defense

The complexity of life is a critical driver of animal biodiversity. Complex phenotypes, which are those that integrate both co-opted and novel features at multiple levels of biological organization (e.g., genes, tissues, behaviors), are commonplace in biology. Many even require other organisms to function, but we know little about how many of these phenotypes evolve. These types of complex phenotypes include the theft of extrinsically generated features of other organisms, including the ability to sequester useful cells, organelles, or chemicals from dietary sources (i.e., their prey). My research centers on investigating the theft of nematocysts, which are stinging organelles exclusively made by members of the phylum Cnidaria. One of the major goals in my lab is to identify the critical genes, tissues, behaviors, etc. that are necessary for the sequestration of nematocysts, and determine the evolutionary steps that led to the origin of this ability in metazoans. In nudibranch gastropods, we have identified at least two origins of the ability to sequester nematocysts, and uncovered evidence for coevolutionary changes between the preference for specific prey types and key morphological changes. We are also using the emerging nudibranch model species, Berghia stephanieae to investigate the nematocyst developmental and physiological mechanisms of nematocyst sequestration. Through this work, we have begun reconstructing the evolutionary history of nematocyst sequestration and its component parts. Ultimately, these investigations into the sequestration of extrinsically produced structures will also provide important insights into how the evolution of complex phenotypes is tied to the fantastic amounts of biodiversity we see today.