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Article: Evolution of cleavage programs in relationship to axial specification and body plan evolution.(Genetic Regulatory Networks in Embryogenesis and Evolution)
- Article from:
- The Biological Bulletin
- Article date:
- December 1, 1998
- Author:
CopyrightCOPYRIGHT 1998 Marine Biological Laboratory. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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We examine egg organization and the role of the early cleavage program in establishing the axial properties of larval and adult body plans. Here we review our own work and that of others on various invertebrate metazoans, including cnidarians, ctenophores, polyclad flat-worms, and some protostome spiralians - nemerteans, molluscs, and polychaete annelids.
The Ctenophores
Most metazoan body plans can be characterized as having, either elements of radial symmetry (such as the Chidaria and Ctenophora) or bilateral symmetry (e.g., protostomes and deuterostomes). Cnidarians are considered to be radially symmetrical around their longitudinal body axis, called ...