Meeting Abstract

S3.3-3  Saturday, Jan. 4 14:30  Old cell new trick: cnidocytes as a model for studying the evolution of novelty BABONIS, L.S.*; MARTINDALE, M.Q.; Whitney Lab for Marine Bioscience, Univ of Florida; Whitney Lab for Marine Bioscience, Univ of Florida babonis@whitney.ufl.edu

Understanding how new cell types arise is critical for understanding the evolution of organismal complexity. Questions of this nature, however, can be difficult to answer due to the challenge associated with defining the identity of a truly novel cell. Cnidarians (anemones, jellies, and their allies) provide a unique opportunity to investigate the molecular regulation and development of cell novelty because they possess a cell that (i) is unique to the cnidarian lineage, and (ii) has a very well-characterized phenotype: the cnidocyte (stinging cell). Because cnidocytes are thought to differentiate from the cell lineage that also gives rise to neurons, cnidocytes express many of the same genes expressed in their neural sister cells. Conversely, only cnidocytes posses a cnidocyst (the explosive organelle that gives cnidocytes their sting); therefore, those genes or gene regulatory relationships specific for the development of the cnidocyst can be expected to be expressed only in cnidocytes. Thus, this system provides an unparalleled opportunity to examine the developmental regulation of both the ancestral and novel components of the cnidocyte and to test the hypothesis that novel cell types evolve as a result of new regulatory relationships between conserved and derived genes. To this end, we review common challenges in the study of evolutionary novelty, introduce the utility of the model cnidarian Nematostella vectensis as a means to advance studies of cellular novelty, and provide evidence for novel regulatory relationships between ancestral genes and novel phenotypes.