Movers and Shakers: The Evolution and Development of Mesoderm

Symposium organized by
Brad Davidson and John Gerhart

Symposium overview

Over the last 5-10 years, a surge of research has begun to illuminate key aspects of comparative mesoderm development and their evolutionary significance (see Technau and Sholz, 2003; Int. J. Dev. Biol. 47: 531-9; Martindale, et al., 2004; Development. 131:2463-74; Oliveri, et al., 2003; Dev. Biol. 258, 32-43; Nishida and Sawada; 2001; Nature 409, 724-9; Lambert and Nagy, 2002; Nature 420, 682-6; Simoes-Costa et al. Dev Biol 277, 1-15). Highlights include evidence for an ancestral metazoan pathway of endo-mesodermal induction through beta-catenin signaling; characterization of the genetic pathways underlying early mesoderm patterning events in the echinoderms, ascidians, vertebrates and molluscs: evidence for shared pathways underlying heart development in arthropods and chordates; extensive work on comparative aspects of gastrulation and mesodermal induction in both arthropods and vertebrates; and novel insights into the role of a retinoic acid gradient in patterning chordate mesodermal organs. Additionally, researchers are poised to examine fundamental questions about mesoderm evolution and development at an unprecedented level of detail. Improved imaging and detailed molecular perturbations permit extensive characterization of the cell movements and behaviors that define mesodermal morphogenesis and a better understanding of the mechanisms that drive such cell behaviors. The genomes of many representative organisms at critical evolutionary junctures have been, or are in the process of being, sequenced. Genome level analysis has already begun in flies, vertebrates and ascidians producing an overwhelming abundance of gene expression data as well as providing the ability to perform detailed examination of comparative gene regulation. Therefore, it is an essential time to help guide and shape this flood of research into productive channels.
This symposium will cover mesoderm evolution from a broad perspective, including researchers studying organisms from 7 distinct phyla. Integration of the data and methodologies from these diverse organisms will permit generation of novel hypotheses regarding mesoderm evolution and the research that will be required to address questions regarding: 1. Basal metazoan evolution; 2. Mechanisms by which evolutionary forces can alter morphogenetic processes and; 3. The extent to which discoveries of developmental processes underlying formation of mesodermal organs in "lower" organisms can be utilized to illuminate conserved processes important for human biology.


We thank SICB, the Divisions of Evolutionary and Developmental Biology and Developmental and Cell Biology, and the Society of Developmental Biology for their sponsorship and generous support.

Schedule of presentations

FRIDAY JAN. 6, 13:00
Session S5-1

Pre-mesoderm: the expression of Wnts during sponge gastrulation and their ancestral role in metazoan development
Bernard M. Degnan and Maja Adamska
School of Integrative Biology, University of Queensland, Australia


An Endodermal Origin of Mesoderm
Patrick Burton*, Kevin Pang***, Cassandra Krone**, Mark Martindale*** and John Finnerty**
*University of Maryland, **Boston University, ***University of Hawaii


A Nanos ortholog is required for endomesoderm specification in the snail Ilyanassa
Evan P. Kingsley, Jeremy Rabinowitz and J. David Lambert*
University of Rochester, Rochester NY


Mesoderm development in arthropods: a view from crustaceans
Alivia L. Price, Nipam Patel


SATURDAY JAN. 7, 08:20
Session S5-2

Introduction
Brad Davison

Role of Nodal in establishment of the sea urchin larva body plan
Veronique Duboc


Evolution of Mesoderm Specification in Echinoderms: Gene Regulatory Network Architectural Reorganization Across Immense Periods of Evolutionary Time
Veronica F Hinman, Eric H Davidson


Ascidian mesoderm specification and the emergence of the chordate body plan
Brad Davidson, UC Berkeley


THE EVOLUTIONARY ORIGIN OF CARDIAC CHAMBERS: ROLE OF RA SIGNALING VIA RALDH2
José Xavier-Neto & Marcos S. Simões-Costa
Laboratório de Genética e Cardiologia Molecular, Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo-SP 05403-900, Brazil


Evolution of Vertebrate Mesoderm Morphogenesis
David Shook and Ray Keller
Univ. of Virginia, Charlottesville

The canonical Wnt pathway and axis formation in Xenopus laevis
Qinghua Tao, Chika Yokota, Matt Kofron, Xinhua Lin and Janet Heasman*
Division of Developmental Biology, Cincinnati Children's Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039