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Germ Line — Soma Differentiation

  • Wolfgang Hennig

Part of the Results and Problems in Cell Differentiation book series (RESULTS, volume 13)

Table of contents

  1. Front Matter
    Pages I-XIII
  2. Back Matter
    Pages 193-196

About this book

Introduction

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.

Keywords

DNA biology cell chromosome developmental biology genome

Editors and affiliations

  • Wolfgang Hennig
    • 1
  1. 1.Department of Genetics, Faculty of SciencesUniversity of NijmegenToernooiveld, NijmegenThe Netherlands

Bibliographic information

  • DOI https://doi.org/10.1007/978-3-540-39838-7
  • Copyright Information Springer-Verlag Berlin Heidelberg 1986
  • Publisher Name Springer, Berlin, Heidelberg
  • eBook Packages Springer Book Archive
  • Print ISBN 978-3-662-21958-4
  • Online ISBN 978-3-540-39838-7
  • Series Print ISSN 0080-1844
  • Series Online ISSN 1861-0412
  • Buy this book on publisher's site