Eeva Therman Human Chromosomes Structure, Behavior, Effects With 55 Figures Springer-Verlag New York Heidelberg Berlin EEYA THERMAN Department of Medical Genetics, University of Wiscon sin, Madison, Wisconsin 53706, USA Library of Congress Cataloging in Publication Data Therman, Eeva. Human chromosomes. Includes bibliographies. 1. Human genetics. 2. Human chromosomes. 3. Human chromosome abnormalities. I. Title. [DNLM: 1. Chromosomes, Human. QH600 T41lh] QH431.T436 611'.01816 80-21278 All rights reserved. No part of this book may be translated or reproduced in any form without written permission from Springer-Verlag. The use of general descriptive names, trade names, trademarks, etc. in this publication, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone. © 1980 by Springer-Verlag New York Inc. Softcover reprint of the hardcover 1s t edition 1980 9 8 7 6 5 4 3 2 1 ISBN-13: 978-1-4684-0109-7 e-ISBN-13: 978-1-4684-0107-3 DOl: 10.1007/978-1-4684-0107-3 For KLAUS PATAU Preface This book provides an introduction to human cytogenetics. It is also suitable for use as a text in a general cytogenetics course, since the basic features of chromosome structure and behavior are shared by all eukar yotes. Because my own background includes plant and animal cytoge netics, many of the examples are taken from organisms other than man. Since the book is written from a cytogeneticist's point of view, human syndromes are described only as illustrations of the effects of abnormal chromosome constitutions on the phenotype. The selection of the phe nomena to be discussed and of the photographs to illustrate them is, in many cases, subjective and arbitrary and is naturally influenced by my interests and the work done in our laboratory. The approach to citations is the exact opposite of that usually used in scientific papers. Whenever possible, the latest and/or most comprehen sive review has been cited, instead of the original publication. Thus the reader is encouraged to delve deeper into any question of interest to him or her. I am greatly indebted to many colleagues for suggestions and criticism. However, my special thanks are due to Dr. JAMES F. CROW, Dr. TRAUTE M. SCHROEDER, and Dr. CARTER DENNISTON for their courage in reading the entire manuscript. I wish to express my gratitude also to the cytogeneticists and editors who have generously permitted the use of published and unpublished photographs. Members of my laboratory have been very helpful in the process of putting this book together. Mrs. BARBARA SUSMAN has been involved in all the phases, from compiling reference lists to designing illustrations. viii Preface The photographic work has been done by Mr. WALTER KUGLER, Jr.; our excellent secretary, Ms. CHRISTINE ONAGA, has cheerfully typed and retyped the manuscript. However, my most special thanks I wish to reserve for the editor of this book, Ms. MARY Lou MOTL. When my Finnish-English emerges from her competent hands, it resembles the text I would have liked to have written in the first place. Madison, Wisconsin EEVA THERMAN September, 1980 Contents I. Past and Future of Human Cytogenetics The Past of Human Cytogenetics ........................... 1 Human Sex Chromosomes ................................ .4 Evolution of Human Chromosomes ........................ .4 Nomenclature of Human Chromosomes ..................... 5 The Future of Human Cytogenetics ......................... 5 Structure of the Eukaryotic Chromosome ................... 6 Mapping of Human Chromosomes ..........................7 Chromosomes and Cancer .................................7 Mutagenesis Studies ......................................7 Cytology of Development .................................8 Clinical Cytogenetics ..................................... 8 References ............................................... 9 II. Structure of the Eukaryotic Chromosome and the Karyotype Metaphase Chromosome ................................. 11 Chromosome Number .................................... 15 Chromosome Size ....................................... 15 Shape of Chromosomes .................................. 16 DNA Content of Nuclei .................................. 17 Human Chromosome Complement ........................ 17 Banded Human Karyotype ............................... 19 Euploid Chromosome Changes ............................ 21 Aneuploid Chromosome Changes ......................... 22 Structural Changes in Chromosomes .......................2 2 References .............................................. 23 x Contents III. Mitotic Cycle and Chromosome Reproduction Significance of Mitosis ................................... 24 Nondisjunction and Loss of Chromosomes .................2 6 Mitotic Cycle ...........................................2 7 Chromosome Replication .................................2 8 References ..............................................2 9 IV. Modifications of Mitosis Endoreduplication .............................. " ....... 30 Endomitosis ............................................ 32 Polytene Chromosomes ..................................3 3 C-Mitosis ............................................... 34 Restitution .............................................. 34 Multipolar Mitoses ......................................3 4 Methods of Studying Endopolyploidy ...................... 34 Somatic Polyploidy and Differentiation .....................3 5 The Role of Somatic Polyploidy in Differentiation ...........3 6 References .............................................. 37 V. Methods in Human CytogenetiCS Direct Methods ......................................... 39 Tissue-Culture Techniques ............................... 040 Meiotic Studies ........................................ Al Sex Chromatin Techniques .............................. Al Autoradiography ....................................... Al Banding Techniques on Fixed Chromosomes .............. 042 Banding Techniques for Cells in Culture .................. 045 Nomenclature of Human Chromosomes ................... 045 References ..............................................4 7 VI. Longitudinal Differentiation of Eukaryotic Chromosomes Prebanding Studies ...................................... 50 Banding Studies on Human Chromosomes .................5 1 Constitutive Heterochromatin ............................. 53 Facultative Heterochromatin .............................. 56 Intercalary Heterochromatin .............................. 56 Chromosome Bands ..................................... 57 Function of Human Chromosome Bands ...................5 8 References .............................................. 59 VII. Chromosome Structural Aberrations Origin of Structurally Abnormal Chromosomes .............6 1 Contents xi Chromosome Breaks and Rearrangements ..................6 2 Chromatid Breaks and Rearrangements ....................6 4 Telomeres ..............................................6 5 Triradial and Multiradial Chromosomes ....................6 6 Centric Fusion ..........................................6 7 Inactivation of the Centromere ............................6 8 Misdivision .............................................6 9 Interphase-like Chromosomes in Metaphase ................6 9 Sister Chromatid Exchanges ..............................7 0 References ..............................................7 0 VIII. Causes of Chromosome Breaks Spontaneous Chromosome Breaks .........................7 3 Points of Weakness in Human Chromosomes ...............7 4 Radiation-Induced Breaks ................................7 4 Chemically Induced Breaks ...............................7 5 Virus-Induced Breaks ....................................7 7 Genetic Causes of Chromosome Breakage ..................7 7 Nonrandomness of Chromosome Breaks ...................7 8 Methods in Chromosome-Breakage Studies .................7 9 References .............................................. 80 IX. The Main Features of Meiosis Significance of Meiosis ...................................8 3 Meiotic Stages ..........................................8 4 Premeiotic Interphase ....................................8 4 Leptotene (or Leptonema) ................................8 6 Zygotene (or Zygonema) .................................8 6 Pachytene (or Pachynema) ................................ 86 Diplotene (or Diplonema) .................................8 9 Diakinesis ..............................................9 0 Metaphase I ............................................9 0 Anaphase I ............................................. 90 Telophase I .............................................9 1 Interkinesis .............................................9 1 Meiotic Division II ......................................9 2 References ..............................................9 3 X. Details of Meiosis Structure of Chiasmata ...................................9 4 Number of Chiasmata ....................................9 4 Synaptonemal Complex ..................................9 6 xii Contents Meiotic Behavior of More Than Two Homologous Chromosomes .........................................9 7 Human Meiosis .........................................9 9 Premeiotic and Early Meiotic Stages in Man ................9 9 Human Meiotic Stages from Diplotene on .......... " ..... 101 Behavior of X and Y Chromosomes ...................... 101 References ............................................. 102 XI. Meiotic Abnormalities Nondisjunction of Autosomes ............................ 104 Nondisjunction of Sex Chromosomes ..................... 105 Misdivision of the Centromere ........................... 106 Environmental Causes of Meiotic Nondisjunction .......... 106 Maternal Age .......................................... 108 Genetic Causes of Nondisjunction ........................ 109 Origin of Diploid Gametes ............................... 110 References ............................................. 110 XII. Human Sex Chromosomes The Y Chromosome .................................... 112 Sex Determination in Man ............................... 113 H-Y Antigen ........................................... 114 Genes on the Y Chromosome ............................ 115 Abnormal Y Chromosomes .............................. 115 The X Chromosome .................................... 115 X Chromatin or Barr Body Formation .................... 116 Inactivation of the X Chromosome ....................... 118 Behavior of X and Y Chromosomes in Meiocytes .......... 121 Sex Reversal Genes .................................... 121 References ............................................. 122 XIII. Sex Chromosome Abnormalities Aneuploidy of X Chromosomes in Individuals with a Female Phenotype .................................... 125 Sex Chromosome Aneuploidy with a Male Phenotype ........................................... 128 Mosaicism ............................................. 129 Abnormal X Chromosomes Consisting of X Material ....... 130 X Inactivation Center ................................... 132 X-Autosomal Translocations ............................. 132 Translocations Involving the Y Chromosome .............. 133 Abnormal X Chromosome Constitutions and the Phenotype ........................................... 133 References ............................................. 134