title: Analysis of morphogenetic mutants of hydra : I. TheAberrant.
abstract: A mutant ofHydra attenuata is analysed, theaberrant, which is distinct from the wild type in having a smaller head with fewer tentacles and only half the number of head-specific cells. The rate of head and foot regeneration and the doubling time are slower inaberrants than in normal hydra.The lower head-forming potential is paralleled by a reduced concentration of head-specific morphogens: compared to the wild type, in theaberrant the concentration of head activator is reduced to 70% in the head and to 50% in the body, the concentration of head inhibitor is reduced to 50% in the head and to 80% in the body. Theaberrant is more sensitive (3 times) to added head activator and less sensitive (>5 times) to added head inhibitor than the wild type.The slower rate of foot regeneration is paralleled by a lower content of foot-specific morphogens: compared to the wild type, in theaberrant the foot activator is reduced to 40% and the foot inhibitor to 70%.
authors.affiliation: European Molecular Biology Laboratory, Postfach 10.2209, D-6900, Heidelberg, Germany.
authors.forename: H C
authors.initials: HC
authors.lastname: Schaller
authors.affiliation: European Molecular Biology Laboratory, Postfach 10.2209, D-6900, Heidelberg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Schmidt
authors.affiliation: European Molecular Biology Laboratory, Postfach 10.2209, D-6900, Heidelberg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Flick
authors.affiliation: European Molecular Biology Laboratory, Postfach 10.2209, D-6900, Heidelberg, Germany.
authors.forename: C J P
authors.initials: CJ
authors.lastname: Grimmelikhuijzen
keywords: Head formation; Hydra mutant; Morphogenetic substances