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Author: W. Hennig Publisher: Springer Science & Business Media ISBN: 3540398384 Category : Science Languages : en Pages : 206
Book Description
One of the oldest problems in developmental biology is the differentiation between germ line and somatic cells. The continuity of germ line cells between subsequent generations of multicellular organisms was first suggested by Owen, and later elaborated by A. Weismann to his famous germ line theory. His additional assumption that cellular differentiation was based on a differential representation of the genetic material in somatic cells was soon disproved. In some, apparently exceptional, cases, however, such differences in the genetic material between germ line and somatic cells were discovered. The best-known example is the nematod Ascaris. Boveri discovered and studied the fundamental differences in the karyotypes of germ line and soma of Parascaris equorum. Later, similar situations were found in some other organisms. However, in particular the work ofSpemann demonstrated that cellular differentiation in general is not accompanied by fundamental changes of the genetic material. Subsequently, the relatively few examples of germ line-soma differences achieved by chromatin elimination processes have been considered as a curiosity. Experimental studies have been essentially restricted to Ascaris species and to the pioneering cytological studies of chromatin elimination by S. Beermann. Despite the large proportions of the genome involved in chromatin elimina tion, our knowledge of this process is still very restricted. In particular the biological meaning of this differentiation process is entirely obscure. In this context one must, however, consider that also for the majority of DNA sequences in eukaryotic genomes the biological relevance is unclear.
Author: W. Hennig Publisher: Springer Science & Business Media ISBN: 3540398384 Category : Science Languages : en Pages : 206
Book Description
One of the oldest problems in developmental biology is the differentiation between germ line and somatic cells. The continuity of germ line cells between subsequent generations of multicellular organisms was first suggested by Owen, and later elaborated by A. Weismann to his famous germ line theory. His additional assumption that cellular differentiation was based on a differential representation of the genetic material in somatic cells was soon disproved. In some, apparently exceptional, cases, however, such differences in the genetic material between germ line and somatic cells were discovered. The best-known example is the nematod Ascaris. Boveri discovered and studied the fundamental differences in the karyotypes of germ line and soma of Parascaris equorum. Later, similar situations were found in some other organisms. However, in particular the work ofSpemann demonstrated that cellular differentiation in general is not accompanied by fundamental changes of the genetic material. Subsequently, the relatively few examples of germ line-soma differences achieved by chromatin elimination processes have been considered as a curiosity. Experimental studies have been essentially restricted to Ascaris species and to the pioneering cytological studies of chromatin elimination by S. Beermann. Despite the large proportions of the genome involved in chromatin elimina tion, our knowledge of this process is still very restricted. In particular the biological meaning of this differentiation process is entirely obscure. In this context one must, however, consider that also for the majority of DNA sequences in eukaryotic genomes the biological relevance is unclear.
Author: Steven X. Hou Publisher: Humana Press ISBN: 9781617378805 Category : Science Languages : en Pages : 0
Book Description
In this comprehensive and cutting-edge book, leading experts explore the parameters that define germline stem cells and the mechanisms that regulate the cell behavior in order to better isolate, characterize and maintain them. The volume begins by providing protocols for germline stem cell identification and regulation in model organisms, and concludes with detailed chapters covering current techniques involving in vitro culture and the applications of the cells.
Author: Michael Buszczak Publisher: Humana ISBN: 9781493940158 Category : Science Languages : en Pages : 0
Book Description
This second edition provides updated and new chapters on selected genetic, molecular, biochemical, and cell biological techniques. Chapter’s guide readers through methods and principles on primordial germ cells and germline stem cells, however many of these principles can be applied to different types of adult stem cells. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Germline Stem Cells: Second Edition aims to present the new findings and techniques that have developed since the first edition.
Author: Thomas Flatt Publisher: OUP Oxford ISBN: 0191621021 Category : Science Languages : en Pages : 506
Book Description
Life history theory seeks to explain the evolution of the major features of life cycles by analyzing the ecological factors that shape age-specific schedules of growth, reproduction, and survival and by investigating the trade-offs that constrain the evolution of these traits. Although life history theory has made enormous progress in explaining the diversity of life history strategies among species, it traditionally ignores the underlying proximate mechanisms. This novel book argues that many fundamental problems in life history evolution, including the nature of trade-offs, can only be fully resolved if we begin to integrate information on developmental, physiological, and genetic mechanisms into the classical life history framework. Each chapter is written by an established or up-and-coming leader in their respective field; they not only represent the state of the art but also offer fresh perspectives for future research. The text is divided into 7 sections that cover basic concepts (Part 1), the mechanisms that affect different parts of the life cycle (growth, development, and maturation; reproduction; and aging and somatic maintenance) (Parts 2-4), life history plasticity (Part 5), life history integration and trade-offs (Part 6), and concludes with a synthesis chapter written by a prominent leader in the field and an editorial postscript (Part 7).
Author: Baruch Rinkevich Publisher: Springer Science & Business Media ISBN: 904812767X Category : Science Languages : en Pages : 376
Book Description
Do real stem cells and stem cell lineages exist in lower organisms? Can stem cells from one organism parasitize the soma and/or the germ line of conspecifics? Can differentiated cells in marine organisms be re-programmed to regenerate tissues, organs and appendages through novel de-differentiation, transdifferentiation, or re-differentiation processes, leading to virtually all three germ layers, including the germline? The positive answers to above questions open a new avenue in stem cell research: the biology of stem cells in marine organisms. It is therefore unfortunate that while the literature on stem cell from terrestrial organisms is rich and expanding at an exponential rate, investigations on marine organisms’ stem cells are very limited and scarce. By presenting theoretical chapters, overview essays and specific research results, this book summarises the knowledge and the hypotheses on stem cells in marine organisms through major phyla and specific model organisms. The study on stem cells from marine invertebrates may shed lights on mechanisms promoting immunity, developmental biology, regeneration and budding processes in marine invertebrates, body maintenance, aging and senescence. It aims in encouraging a larger scientific community to follow and study the novel phenomena of stem cells behaviours as depicted from the few currently studied marine invertebrates.
Author: Publisher: Academic Press ISBN: 0080584608 Category : Science Languages : en Pages : 447
Book Description
In spite of the fact that the process of meiosis is fundamental to inheritance, surprisingly little is understood about how it actually occurs. There has recently been a flurry of research activity in this area and this volume summarizes the advances coming from this work. All authors are recognized and respected research scientists at the forefront of research in meiosis. Of particular interest is the emphasis in this volume on meiosis in the context of gametogenesis in higher eukaryotic organisms, backed up by chapters on meiotic mechanisms in other model organisms. The focus is on modern molecular and cytological techniques and how these have elucidated fundamental mechanisms of meiosis. Authors provide easy access to the literature for those who want to pursue topics in greater depth, but reviews are comprehensive so that this book may become a standard reference.Key Features* Comprehensive reviews that, taken together, provide up-to-date coverage of a rapidly moving field* Features new and unpublished information* Integrates research in diverse organisms to present an overview of common threads in mechanisms of meiosis* Includes thoughtful consideration of areas for future investigation
Author: Swathi Arur Publisher: Springer ISBN: 331944820X Category : Science Languages : en Pages : 296
Book Description
This volume covers the current knowledge base on the role of signaling and environmental pathways that control the normal development of germline stem cells, meiotic progression of oocytes, events of oocyte maturation and fertilization, and the birth of an embryo. Germ cells are uniquely poised to sustain life across generations through the fusion of oocyte and sperm. Because of the central importance of germ cells to life, much work has been dedicated to obtaining a clear understanding of the molecular and signaling events that control their formation and maintenance. Germ cells are set aside from somatic cells in the embryo and go through specialized meiotic cell cycles as the animal matures. These cell cycles are interspersed with long periods of arrest. In human females, meiosis I is initiated in the fetus. At birth, oocytes are arrested in meiosis I; after puberty, every month an oocyte initiates meiosis II – ovulation. Upon sperm availability these cells are fertilized, generate an embryo, and the cycle-of-life continues. During meiotic I progression and arrest, the fitness of oocytes and their progeny are likely influenced by environmental cues and signaling pathways. A lot of recent work has focused on understanding the mechanisms that regulate oocyte fitness and quality in humans and vertebrates. Much of our understanding on the events of meiosis I and germline stem cell populations comes from work in invertebrates, wherein the germline stem cells produce oocytes continuously through adult development. In both inverbrates and vertebrates nutritional and signaling pathways control the regulation of stem cells in such a manner so as to couple production of gametes with the nutritional availability. Additionally, mature oocytes arrest both in meiosis I and meiosis II, and signaling and nutritional pathways have been shown to regulate their formation, and maintenance, such that despite long periods of arrest, the oocyte quality is assured and errors in chromosome segregation and varied cytoplasmic events are minimal.
Author: W. Hennig
Author: W. Hennig
Author: Steven X. Hou
Author: David L. Kirk
Author: Michael Buszczak
Author: August Weismann
Author: Thomas Flatt
Author: Baruch Rinkevich
Author: 
Author: 
Author: Swathi Arur