In a previous paper (Webster & Wolpert, 1966a) it was shown that during regulation the time required for the determination of the dominant region, the hypostome, was dependent on the original position of the hypostome-forming region on the linear axis. Hypostome determination occurred more quickly from distal than from proximal regions, suggesting an axial gradient. As Spiegelman (1945) has pointed out, a gradient in time for determination is not sufficient for limited realization to occur in a regulative system (Webster & Wolpert, 1966a). In addition, some mechanism for suppressing potentialities is required. One of the characteristic features of a dominant region is that it inhibits the formation of a new dominant region (Huxley & de Beer, 1934), and earlier work on hydra (Rand, Bovard & Minnich, 1926) has presented some evidence for inhibition of distal regeneration by distal structures. This paper will be concerned with a detailed analysis of the factors controlling hypostome formation.
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Journal Article| 01 August 1966
Studies on pattern regulation in hydra: II. Factors controlling hypostome formation
Zoology Department, King's College, University of London
1Author's address: Strangeways Research Laboratory, Wort's Causeway, Cambridge, England.
Received: 28 Jan 1966
Online Issn: 1477-9129
Print Issn: 0950-1991
Copyright © 1966 by Company of Biologists
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Gerald Webster; Studies on pattern regulation in hydra: II. Factors controlling hypostome formation. Development 1 August 1966; 16 (1): 105–122. doi: https://doi.org/10.1242/dev.16.1.105
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