Stanford University

Echinoderms – natural experiments in body plans

 

Echinoderms are one of the most intriguing of the metazoan phyla. As one of the four deuterostome phyla, they are the sister group to hemichordates and closely related to chordates. The extant members are divided into 5 classes, the sea urchins or echinoids, starfish (asteroids), brittle stars (ophiuroids), sea cucumbers (holothuroids), and sea lilies or feather stars (crinoids). The adult body plan of these animals is highly modified and derived in relation to the other deuterostome groups: the most striking element of their body plan is the five-fold radial symmetry; most apparent in the asteroids and ophiuroids. We are interested in the evolutionary steps leading to the transformation of the ancestral bilaterian deuterostome into this unusual and highly modified body plan.

Molecular genetics of the patterning of the adult radial body plan:  We are interested in the formation of the adult body plan so rear larvae through metamorphosis and investigate gene expression during the development of the juvenile body plan.  We are using our work in hemichordates as a model to characterize the early developmental genetics of adult body patterning asteroid Patiria miniata and the holothuroid Parastichopus parvimensis.

 

Relevant Publications: 

  • Lowe, C.J. and Wray G.A.. Radical alterations in the roles of homeobox genes during echinoderm evolution. Nature 389: 718-721

  • Wray G.A., Lowe C.J. Developmental regulatory genes and echinoderm evolution. Systematic Biology 49(1): 28-51

  • Lowe C.J., Issel-tarver, L., Wray G. A., Gene recruitment and early life history evolution of echinoderms. Evolution and Development 4 (2): 111-123.