Early Embryonic Development Of Animals

Four of the major animal systems studied for the mechanisms of their early embryonic development are treated in this volume. The articles address the specific questions studied in the various systems, discuss the fundamental questions raised by the particular organism and explain the techniques used to find answers to these questions. Questions of patternformation, early organogenesis and the genetics of the early development arecovered as well as the question of parental imprinting phenomena in mammals which are important for the early differentiation. The development of the mouse, Drosophila, Caenorhabditis and the zebrafish is emphasized by leading experts of their fields, and current problems in each system are exposed. For the zebrafish the advantages of this new system for developmental biology studies are summarized and discussed in their values, while in the other system the emphasis is laid on one of the actual field of research.

Eggs of all animals contain mRNAs and proteins that are supplied to or deposited in the egg as it develops during oogenesis. These maternal gene products regulate all aspects of oocyte development, and an embryo fully relies on these maternal gene products for all aspects of its early development, including fertilization, transitions between meiotic and mitotic cell cycles, and activation of its own genome. Given the diverse processes required to produce a developmentally competent egg and embryo, it is not surprising that maternal gene products are not only essential for normal embryonic development but also for fertility. This review provides an overview of fundamental aspects of oocyte and early embryonic development and the interference and genetic approaches that have provided access to maternally regulated aspects of vertebrate development. Some of the pathways and molecules highlighted in this review, in particular, Bmps, Wnts, small GTPases, cytoskeletal components, and cell cycle regulators, are well known and are essential regulators of multiple aspects of animal development, including oogenesis, early embryogenesis, organogenesis, and reproductive fitness of the adult animal. Specific examples of developmental processes under maternal control and the essential proteins will be explored in each chapter, and where known conserved aspects or divergent roles for these maternal regulators of early vertebrate development will be discussed throughout this review. Table of Contents: Introduction / Oogenesis: From Germline Stem Cells to Germline Cysts / Oocyte Polarity and the Embryonic Axes: The Balbiani Body, an Ancient Oocyte Asymmetry / Preparing Developmentally Competent Eggs / Egg Activation / Blocking Polyspermy / Cleavage/ Mitosis: Going Multicellular / Maternal-Zygotic Transition / Reprogramming: Epigenetic Modifications and Zygotic Genome Activation / Dorsal-Ventral Axis Formation before Zygotic Genome Activation in Zebrafish and Frogs / Maternal TGF-β and the Dorsal-Ventral Embryonic Axis / Maternal Control After Zygotic Genome Activation / Compensation by Stable Maternal Proteins / Maternal Contributions to Germline Establishment or Maintenance / Perspective / Acknowledgments / References

This comprehensive and cogent survey examines the subject of embryonic determination, the set of processes fundamental to animal development by which cells in the early embryo acquire different developmental capabilities. Examining both the classical literature and the newer, molecular findings, the author summarizes the current state of our understanding of determination and poses key questions for the future. He begins with a consideration of how much spatial pattern is already laid down when the egg forms inside the mother, and ends just before the formation of visible organs. Within these limits he also considers evidence obtained by a variety of techniques, both experimental and biochemical, derived from the embryos of a variety of animal groups. This is a suitable text for upper level undergraduates, graduate students and researchers in developmental biology.

This book vividly describes how complex and integrated movements can arise from the properties and behaviors of biological molecules. It provides a uniquely integrated account in which the latest findings from biophysics and molecular biology are put into the context of living cells. This second edition is updated throughout with recent advances in the field and has a completely revised and redrawn art program. The text is suitable for advanced undergraduates, graduate students, and for professionals wishing for an overview of this field.

Recent scientific breakthroughs, celebrity patient advocates, and conflicting religious beliefs have come together to bring the state of stem cell researchâ€"specifically embryonic stem cell researchâ€"into the political crosshairs. President Bush's watershed policy statement allows federal funding for embryonic stem cell research but only on a limited number of stem cell lines. Millions of Americans could be affected by the continuing political debate among policymakers and the public. Stem Cells and the Future of Regenerative Medicine provides a deeper exploration of the biological, ethical, and funding questions prompted by the therapeutic potential of undifferentiated human cells. In terms accessible to lay readers, the book summarizes what we know about adult and embryonic stem cells and discusses how to go about the transition from mouse studies to research that has therapeutic implications for people. Perhaps most important, Stem Cells and the Future of Regenerative Medicine also provides an overview of the moral and ethical problems that arise from the use of embryonic stem cells. This timely book compares the impact of public and private research funding and discusses approaches to appropriate research oversight. Based on the insights of leading scientists, ethicists, and other authorities, the book offers authoritative recommendations regarding the use of existing stem cell lines versus new lines in research, the important role of the federal government in this field of research, and other fundamental issues.

Living Embryos: An Introduction to the Study of Animal Development covers the growth of an animal embryo, specifically the sequence developmental events of an egg. This book addresses the mammalian embryo as a homograph and demonstrates early vertebrate development mechanisms. Some of the topics covered in the book are the early embryology, development, and growth of the frog, mammals, chick, rabbit, arthropods, polychaetes, nematodes, molluscs, and tunicates. Other chapters deal with the formation of the nervous, muscular, and alimentary systems. These topics are followed by the analysis of the development of fishes. The discussion then shifts to the method of fertilization. The last chapters examine the formation of cleavage, cleavage geometry, embryonic membranes, and organization of the egg. The book can provide useful information to embryologists, biologists, students, and researchers.