Figure 1

To understand the evolution of morphological diversity, researchers are turning to lesser known organisms. (a) The offspring of Euprymna scolopes, a sepiolid squid studied by Heinz de Couet (University of Hawaii, Honolulu, USA), display nested expression of Hox genes during development of the cephalopod arm crown. (b) Matthias Gerberding of Nipam Patel's lab (University of Chicago, USA) described studies of the crustacean Parhyale hawiensis, whose embryos (stained for Engrailed protein, in red, and DNA, in blue) develop a distinct grid of cell rows not observed in embryos of model arthropods. By comparing allele frequencies in (c) limnetic and (d) benthic species of the three-spine stickleback, Katie Peichel (Stanford University, USA) seeks to identify genetic changes underlying morphological evolution. (e) Laura Katz (Smith College, Northampton, USA) discussed the diversity of ciliates, such as Halteria grandinella (shown here immediately after division), and the developmentally regulated genome rearrangements that mark their somatic and germline nuclei. (f) Tardigrades, an intermediate group between nematodes and arthropods, have a small number of cells whose lineages are being mapped by Bob Goldstein (University of North Carolina, Chapel Hill,USA) in an effort to develop a new system for experimental embryology. Images courtesy of (a) Patricia Lee; (b) William Browne and Nipam Patel; (c) and (d) Katie Peichel; (e) Lasek-Nesselquist, Salcedo, Briggs and Katz; (f) Diane Nelson.