The Vertebrate Organizer

The organizer area plays a central role in the formation of the embryonic axis and the central nervous system of all vertebrates including the human fetus. In The Vertebrate Organizer, outstanding molecular development biologists and embryologists report their latest approaches in this fascinating research area using different vertebrate model organisms. The presented data is of central importance for the understanding of early human embryogenesis.

This book provides new insights into the universality of biological systems in animal reproduction and development by a comparative study of a variety of mechanisms in animals ranging from basal invertebrates to vertebrates, including mammals. Animals accomplish genetic diversity through meiosis and fertilization, and during embryogenesis animals must produce specialized cell types, including germ cells, in accordance with their individual body plan. This series of phenomena is essential to the continuity of life in the animal kingdom, and animals show various reproductive and developmental strategies. This volume, comprising four parts, reviews animal kingdom diversity, including reproductive strategies and germ cell differentiation mechanisms (Part 1), sex determination and differentiation (Part2), the mechanisms of fertilization (Part 3), and body axis formation (Part 4). Readers will find descriptions of the reproduction or development of 180 species, 13 phyla, 35 classes, 74 orders, 117 families, and 151 genera in this book. Of particular interest is the diversity of molecules and mechanisms used to achieve the same biological purpose in different animals. Undergraduates, graduate students, and professional scientists who want a deeper understanding of animal reproductive and developmental mechanisms will find this book to be of great value.

This book is the product of a NATO Advanced Study Institute of the same name, held at the Anargyrios and Korgialenios School on the island of Spetsai, Greece, in September 1994. The institute considered the molecular mechanisms which generate the body plan during vertebrate embryogenesis. The main topics discussed included: commitment and imprinting during germ cell differentiation; hierarchies of inductive cell interactions; the molecular functioning of Spemann's organizer and formation of embryonic axes; the extracellular matrix and the cytoskeleton in relation to morphogenesis and cell migration; neurogenesis and patterning of the neuraxis; the regulation of pattern formation by Hox genes and other transcription factors. This ASI was marked by a number of special features. An important one was that it brought together three different generations of embryologists: pioneers in classical embryology; scientists who are now leading the present molecular elucidation of vertebrate embryogenesis; and the promising younger ASI participants, some of whom are already making important contributions to this field. This aspect was very important in determining the character of the meeting. It exposed ambiguities in the classical embryological dogma and thus facilitated a subtle application of the recent molecular findings to classical problems. The second shining feature of this ASI was its evolutionary emphasis. The findings presented were obtained in four different vertebrate systems: mammals (the mouse), avians (the chicken), amphibians (Xenopus) and the teleost fishes (zebrafish).

Wnt genes code for a family of secreted glycoproteins which fulfil important functions during the development of vertebrates and invertebrates. Wnts regulate as different aspects as differentiation, proliferation, cell migration, and cell polarity. Wnt proteins are able to activate different intracellular signaling cascades. This book describes different aspects of Wnt signaling during development of different species like the mouse, Xenopus, chicken, C. elegans or Drosophila and in different cellular contexts like heart formation or limb bud patterning. By doing such, this book provides, for the first time in printed form, an overview of the function of Wnt proteins during development. This book will be of interest to all professionals in the field of Wnt signaling, signal transduction or animal development.

Current Topics in Developmental Biology, Volume 45 surveys the major issues at the forefront of developmental biology. This volume, like others in the serial, is valuable to researchers in the fields of animal and plant development, and to students and other professionals who want an introduction to current topics in cellular and molecular approaches to developmental biology. Chapters on the nervous system, reproductive system, and flowering introduce new models and concepts for understanding these processes. Includes development of the nervous and reproductive systems Covers flowering in plants Highlights the roles of homeobox-related transcription factors and growth factors in axis and organ development