CONTENTS Main Page Dynamic Development The Foundations of Developmental Biology Gametogenesis From Sperm and Egg to Embryo Genetic Regulation of Development Organizing the Multicellular Embryo Generating Cell Diversity Dynamic Development at a Glance Learning Resources Research Resources The Developmental Biology Journal Club Developmental Biology Tutorial

Organizing the Multicellular Embryo How does the zygote acquire the complex shape of the adult organism? Gastrulation marks the onset of changes in cell behavior that begin to shape the organism. As a consequence of gastrulation, the embryo becomes a trilaminar entity, with an outer layer of ectoderm, an inner endoderm and an intermediate layer of mesoderm. Cells of these layers then assemble into the organ and tissue rudiments and, ultimately, the functional organs and tissues that characterize the adult. Cells can undergo changes either autonomously or in conjunction with their neighbors to form the embryo. Obviously, the consequences of changes in cell shape and motility will be quite different if cells are joined in an epithelium than when they are unconstrained by neighbors. The major morphogenetic process that involve mesenchymal and epithelial cells during embryogenesis are summarized by Gilbert (1997), Fig. 3.1 and by Kalthoff (1996), Fig. 10.3. We shall now examine the following mechanisms of morphogenesis in detail, based upon recent progress in the field. Cell Motility How do cells move? Intercellular Adhesion What makes cells sticky? References Gilbert, S.F. 1997. Developmental Biology. Fifth edition. Sinauer. Sunderland, MA. Kalthoff, K. 1996. Analysis of Biological Development. McGraw-Hill. New York.

Dynamic Development at a Glance Main Page Dynamic Development

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This material may be reproduced for educational purposes only provided credit is given to the original source. Leon Browder & Laurie Iten (Ed.) Dynamic Development Last revised Thursday, June 25, 1998