General embryological information service - HPS Repository

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W.NAGL. 1978. ENDOPOLYPLOIDY AND POLYTENY IN DIFFERENTIATION AND EVOLUTION;
towards an understanding of quantitative and qualitative variation of nuclear
DNA in ontogeny and phylogeny
North-Holland, Amsterdam, etc. XIV, 283 pp., 154 figs., 26 tabs., combined
taxonomic and subject indexes. $ 54.50, Df1.125.00
Contents: 1. Organization of the eukaryotic chromosome, 2. Occurrence and
characterization of endopolyploid nuclei, 3. Mechanisms of endopolyploidization,
4. Further mechanisms of nuclear DNA variation, 5, Control of endopolyploidization
and polytenization, 6. Functional significance of endocycles,
7. Evolutionary aspects
The main value of this book for our readers lies in the fact that it brings
together a mass of data from both animals and plants showing that endopolyploidy
is a much less exceptional phenomenon than many biologists think. I
quote from Chapter One: "It is one of the chief intentions of the present
work to demonstrate that the nucleus and its DNA and chromatin exhibit a
dynamic organization rather than a constant one. The collection of data on
endopolyploidy and differential DNA replication may show that most cells of
most organisms do have quantitatively and qualitatively different DNAs in
their nuclei. The extensive review of the data offers the chance to understand
developmental variation of DNA and chromatin as an important factor in
gene regulation and cell differentiation". The author feels that this DNA
variation is involved both in the characteristic form and function of a
species and in its realisation during development.
The table of contents above speaks for itself. In ch.6 most of the experimental
evidence cited derives from insect and particularly plant studies
(many of them by the author and his associates). At the end of ch.7 the
author presents a "DNA optimisation model" to account for some relationships
between nuclear DNA variation during ontogenesis, anagenesis and cladogenesis
He ends by expressing support for a recent statement by Britten and Davidson's
group to the effect that "divergence during phylogenesis and ontogenesis
are two sides of the same coin, or, in other words, speciation and differentiation
are two sides of DNA variation".
The book is concluded by a glossary and a guide to the literature pertaining
to methods (molecular-biological and otherwise) . The bibliography runs
into 1977 and covers 50 pages of small print. The book is beautifully produced
and superbly illustrated.
A.NESSI de AVINON. 1977. LAS CE!luLAS ROJAS; fundamentos bio-f isiologicos de
la eritropoyesis (The red blood cells; bio-physiological foundations of erythropoiesis)
(in Spanish)
Celcius, Buenos Aires. 169 pp., 51 figs., 5 tabs.
Contents (translated): 1. Mechanisms of differentiation, 2. Specific proteins,
3. The red cell series, 4. The hemopoietic stem cell, 5. Hemopoietic
organs, 6. Erythropoietin, 7. The ery thro-inhibitory factor
Modern treatment of the subject in the framework of developmental biology
(chs.l and 2); brief introduction on homeostatic laws and cell populations;
emphasis on cell interactions; literature largely up to 1973, occasionally
later; illustrated with diagrams and micrographs.
216
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