The Metamorphosis Antidote

  title={The Metamorphosis Antidote},
  author={Shinichi Nakagawa and William A Harris},
What if you woke up one morning and your eyes were on the top of your head? You would be confused to see the sky in front of you and would worry that if you took a step to the rear you would smash into the ground. This could never happen unless you lived in a Kafka-esque story and had been transformed into a giant clawed frog. Xenopus really do experience such a change in the position of their eyes during their Metamorphosis, but they have an antidote to this disorienting morphogenetic movement… 


Ocular migration and the metamorphic and postmetamorphic maturation of the retinotectal system in Xenopus laevis: an autoradiographic and morphometric study.
  • S. Grant, M. Keating
  • Biology, Medicine
    Journal of embryology and experimental morphology
  • 1986
It was found that the asymmetry of retinal growth from metamorphic climax was that required to stabilize retinal visual field positions with respect to body position, and this minimizes the requirements for visuomotor readjustments that would otherwise be necessary to compensate for a situation in which eye position, relative to the body, is changing.
Retinal growth in double dorsal and double ventral eyes in Xenopus.
The characteristic histogenetic pattern of the dorsal and ventral retinal halves was maintained in an ectopic position in the compound eye, indicating that this particular property of the Retinal halves is intrinsically determined.
Post-metamorphic eye migration in Rana and Xenopus
It is predicted that Rana might exhibit substantially less post-metamorphic eye migration than Xenopus, and results are reported which confirm this prediction.
Patterns of cell proliferation in the retina of the clawed frog during development
It is proposed that the asymmetrical retinal growth serves to maintain the relationship between each point in visual space and corresponding points in the two retinae as the eyes are displaced dorsally on the head during metamorphosis.
Control of the development of the ipsilateral retinothalamic projection in Xenopus laevis by thyroxine: results and speculation.
  • S. Hoskins
  • Biology, Medicine
    Journal of neurobiology
  • 1986
Results indicate that the development of the ipsilateral retinothalamic projection is dependent upon thyroxine, and strongly suggest that the hormone acts at the level of the eye, rather than at the optic chiasm or thalamic target, to bring about theDevelopment of a new pathway.
The genetic sequence of retinal development in the ciliary margin of the Xenopus eye.
A spatial ordering of gene expression is predicted that predicts a genetic hierarchy governing vertebrate retinogenesis, corroborating some of the relationships between genes predicted to act sequentially.
Differential growth of the neural retina in Xenopus laevis larvae.
During late larval stages ofXenopus laevis the neural retina increases in area in concert with the increase in diameter of the eye. At the same time there is an increase in thickness of the inner
Asymmetric Growth and Development of the Xenopus laevis Retina during Metamorphosis Is Controlled by Type III Deiodinase
It is shown that dorsal CMZ cells express type III deiodinase (D3), an enzyme that inactivates TH that accounts for the asymmetric growth of the frog retina.
Developmental and regional expression of thyroid hormone receptor genes during Xenopus metamorphosis.
Exposure of tadpoles at premetamorphic stages to exogenous thyroid hormone (T3) substantially enhanced the accumulation of TR mRNA, especially that of TR beta message, which could explain the accelerated increase in sensitivity of tadPoles to thyroid hormones at the onset of natural metamorphosis.
Drosophila tissues with different metamorphic responses to ecdysone express different ecdysone receptor isoforms
This work uses isoform-specific monoclonal antibodies to show that at the onset of metamorphosis different ecdysone target tissues express different isoform combinations in a manner consistent with the proposition that the different metamorphic responses of these tissues require different combinations of the EcR isoforms.