SICB Annual Meeting 2010
January 3-7, 2010
Seattle, WA

Symposium: Spiralian development: Conservation and innovation

Spiralian development is the dominant mode of early development among a large group of protostomes phyla called the Lophotrochozoa. This clade includes roughly a third of the animal phyla and exhibits the highest degree of animal body plan diversity among the three superclades of bilaterian animals. Spiralian development is characterized by 1) a stereotyped pattern of early asymmetric cell division called spiral cleavage, 2) similarities in the pattern of cell fates in the blastula, and 3) similarities in larval morphology. Recent phylogenetic studies indicate that the common ancestor of the Lophotrochozoa had spiralian development, highlighting the importance of this character for understanding the evolutionary history of animal diversification and animal development. There are also particular advantages for studies of the evolution of development within the spiralians. The strong conservation of spiralian development means that homology can be recognized at the level of individual cells in the embryos of distantly related phyla, and many aspects of the common ancestor of spiralians can be reliably predicted. Against this backdrop of conservation, there is a wealth of evolutionary novelty, both subtle and dramatic.

This symposium is sponsored by:



The major goal of this symposium is to foster communication among groups that are working on the developmental biology of members of the clade Lophotrochozoa (=Spiralia). We intend to define core spiralian developmental mechanisms, and identify elaborations and modifications of these conserved mechanisms. Given the significant changes in the field in the last few years, including new functional methods, improved phylogenetic resolution, and genomic data, this meeting is expected to transform understanding of this important character set, and generate new questions and collaborations.

Organized by: J. David Lambert, University of Rochester and Elaine Seaver, University of Hawaii

Preliminary Schedule

S9.1 Wednesday, Jan. 6, 08:00 MEYER, N. P.; BOYLE, M. J.; MARTINDALE, M. Q.; SEAVER, E. C.*: The complete cell lineage of the polychaete annelid Capitella teleta

S9.2 Wednesday, Jan. 6, 08:30 HENRY, JJ*; PERRY, KJ: Cell and molecular mechanisms involved in the establishment of the D quadrant in the Gastropod, Crepidula fornicata

S9.3 Wednesday, Jan. 6, 09:00 SHANKLAND, M.*; SCHMERER, M.W.; NULL, R.W.: Paxβ: a lophotrochozoan gene family implicated in spiral cleavage

S9.4 Wednesday, Jan. 6, 09:30 MASLAKOVA, S.A.: The invention of the pilidium larva in an otherwise perfectly good spiralian phylum Nemertea.

S9.5 Wednesday, Jan. 6, 10:30 SCHNEIDER, Stephan Q: Symmetry makers and symmetry breakers: the transition of a spiral cellular arrangement to bilateral symmetry in early embryos of Platynereis dumerilii

S9.6 Wednesday, Jan. 6, 11:00 GHARBIAH, M; NAKAMOTO, A; NAGY, L*: The role of the polar lobe and intracellular signaling in cell fate specification of the mud snail Ilyanassa.

S9.7 Wednesday, Jan. 6, 11:30 MARTINDALE, Mark Q.*; LEE, Patricia; HENRY, Jonathan Q.: The development of the mesentoblast in the gastropod Crepidula fornicata

S9.8 Wednesday, Jan. 6, 13:00 WEISBLAT, D.A.*; CHO, S.J.; LYONS, D.C.; VALLéS, Y.; WANG, J.K.: D quadrant specification in a leech (Helobdella; sp.): comparison with other spiralians

S9.9 Wednesday, Jan. 6, 13:30 HEJNOL, A*; PASSAMANECK, YQ; MARTINDALE, MQ: Understanding the non-spiral members of the clade Spiralia: The development of the digestive system of the brachiopod Terebratalia transversa

S9.10 Wednesday, Jan. 6, 14:00 GRANDE, Cristina: The left-right axis. Generating asymmetries in snail development.

S9.11 Wednesday, Jan. 6, 14:30 LAMBERT, J D: Cracking the code of the spiralian quartets: RNA segregation in Ilyanassa