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Susumu Ohno:

Chordata 1. Protochordata, Cyclostomata and Pisces

1974. VIII, 92 pages, 7 figures, 6 tables, 16x25cm, 330 g
Language: English

(Animal Cytogenetics, Volume 4)

ISBN 978-3-443-26001-9, paperback, price: 23.00 €

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Contents

Contents top ↑

Introduction V
1 Genome size and the number of genes 1
1.1 Mutation load and the number of gene loci an organism can afford 2
1.2 Why so much trivial DNA?
1.3 Repeated base sequences which are functional genes 10
1.4 Multitudes of "trivial" DNA 12
1.4.1 Constitutive heterochromatin and repetitious DNA 12
1.4.2 Trivial DNA as an untranscribable spacer between two adjacent
functional genes 15
1.4.3 Trivial DNA which is transcribed together with adjacent functional
genes 16
1.5 The importance of doing nothing 17
2 Polyploid evolution 19
2.1 Triploidy and the gynogenic all female species: The story of the Amazon
molly (Poecilia formosa, Cyprinodontiformes) 20
2.2 Trout, salmon, whitefish and grayling as bisexual tetraploids in the
process of diploidization 22
2.3 Are carp and goldfish older tetraploids? 28
3 Genome size changes without chromosomal changes and the enigma
of 4S acrocentrics 32
3.1 The meaning of genome size increase by means other than polyploidy 33
3.2 Chromosomal changes and speciation 36
3.3 The enigma of 48 acrocentrics 38
4 Sex chromosomes and sex determining mechanisms 46
4.1 Synchronous hermaphroditism 49
4.2 Asynchronous hermaphroditism 50
4.3 Sex reversal and identification of the homogametic sex in bisexual teleost
species by steroid hormones and other means 51
4.4 Still extensive homology between the X and the Y or the Z and the W in
fish 5 3
4.5 Heteromorphic sex chromosomes reported in certain fish species 55
4.6 Heteromorphic chromosomes reported in fish of unspecified sex 57
4.7 Difficulty of reconciliation between sex chromosome heteromorphism
and other known facts 59
5 Primitive fish and the evolution of vertebrates 63
5.1 Tunicates, Amphioxus, and Cyclostomes 64
5.2 Elasmobranchs, holocephalians, chondrosteans and holosteans 68
5.3 Lungfish and coelacanth 70
6 Population cytogenetics of teleosts 71
6.1 Atlantic and Pacific species 72
6.2 Anadro mous fish 74
6.3 Catadromous fish 74
6.4 Identification of larval forms 75
6.5 Identification of interspecific hybrids 76
References 77
Subject index 89