Symposium reports 



8. 



J. D. COWAN, ed. 1972. SOME MATHEMATICAL QUESTIONS IN BIOLOGY, II 

 Am.Mathem.Soc . , Providence. Lectures on Mathematics In the Life 

 Sciences Vol.3. VIII, 121 pp., 15 figs., author and subject In- 

 dexes. $ 6.00 (paper) 



Contents: 1. Models of clocks and maps In developing organisms 

 (M.H.Cohen); 2. Periodic wave propagation and pattern forma- 

 tion: application to problems in development (J.Cooke and B.C. 

 Goodwin); 3. The organization of cellular genetic control sys- 

 tems (S.Kauffman) 



This volume contains lectures presented at a Symposium held 

 in Boston in December, 1969. The long time elapsed before publi- 

 cation somewhat detracts from their topicality. Nevertheless, 

 it is convenient to have together in compact format the thoughts 

 of some of the world's leading theoretical biologists who occupy 

 themselves with the baffling problem of how developing organisms 

 convert into temporal and spatial patterns the messages produced 

 by their genes. After the establishment of the theory of selec- 

 tive gene activation this surely is the next major concern of 

 developmental biology. 



Cohen discusses various models for pattern formation based 

 either on material fluxes or on organizing waves. In the latter 

 section he contrasts Goodwin and Cohen's original phase shift 

 model with a simpler single-event model and with a model based 

 on a combination of periodic events and diffusion. Cooke and 

 Goodwin apply the general concept of organizing waves to Hydra 

 and to early amphibian development. This essay is the most con- 

 crete in content and may therefore appeal most to the average 

 embryologist . It extensively discusses positional information 

 in the mesoderm of the amphibian neurula, and suggests meaning- 

 ful experiments to test the model. (It is a pity that the au- 

 thors were not aware of the recent discovery of mesoderm induc- 

 tion in the amphibian blastula at the time of writing.) 



Kauffman's essay is the longest and deals with the organism 

 viewed as a switching net of binary units with few inputs (the 

 genes), which is characterized by "forcing structures" respon- 

 sible for homeostasis. Among other things, the author discusses 

 the biological implications of his model for cell cycle time, 

 number of cell types as related to amount of DNA per cell, re- 

 stricted pathways of differentiation (illustrated by transde- 

 termination in Drosophila), and capacity of the system to 

 evolve while retaining basic cell types. This discussion leads 

 to the suggestion that two types of genes may exist, called de- 

 velopmental and cell-type genes respectively. 



INVERTEBRATE DEVELOPMENT (general ) (no entries, but see nr. 58) 



VERTEBRATE DEVELOPMENT (general) (see also 27,33,70,91) 



Treatises 



9. 



W.S.HOAR and D.J.RANDALL, eds. I969. PISH PHYSIOLOGY, vol.3. 

 Reproduction and growth; bioluminescence, pigments, and poisons 

 Academic Press, New York, etc. XVI, 485 pp., 72 figs., 34 tabs., 

 author, systematic, and subject Indexes. $ 24.00 



This is only one volume of a six-volume multi-author treatise, 

 but it is the only one that deals with aspects of fish develop- 

 ment, growth, and reproduction in three of its chapters. 



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