Pickering, J. and Towers, M. (2016) Inhibition of Shh signalling in the chick wing gives insights into digit patterning and evolution. Development, 143 (19). pp. 3514-3521. ISSN 0950-1991
Abstract
In an influential model of pattern formation, a gradient of Sonic hedgehog (Shh) signalling in the chick wing bud specifies cells with three antero-posterior positional values, which give rise to three morphologically different digits by a self-organizing mechanism with Turing-like properties. However, as four of the five digits of the mouse limb are morphologically similar in terms of phalangeal pattern, it has been suggested that self-organization alone could be sufficient. Here, we show that inhibition of Shh signalling at a specific stage of chick wing development results in a pattern of four digits, three of which can have the same number of phalanges. These patterning changes are dependent on a posterior extension of the apical ectodermal ridge, and this also allows the additional digit to arise from the Shh-producing cells of the polarizing region - an ability lost in ancestral theropod dinosaurs. Our analyses reveal that, if the specification of antero-posterior positional values is curtailed, self-organization can then produce several digits with the same number of phalanges. We present a model that may give important insights into how the number of digits and phalanges has diverged during the evolution of avian and mammalian limbs.
Metadata
Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016. Published by The Company of Biologists Ltd | ||||
Keywords: | Chick development; Digits; Limb; Positional information; Self-organization; Shh | ||||
Dates: |
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Institution: | The University of Sheffield | ||||
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Biosciences (Sheffield) > Department of Biomedical Science (Sheffield) | ||||
Funding Information: |
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Depositing User: | Symplectic Sheffield | ||||
Date Deposited: | 20 Oct 2016 14:00 | ||||
Last Modified: | 23 Oct 2018 13:04 | ||||
Published Version: | https://dx.doi.org/10.1242/dev.137398 | ||||
Status: | Published | ||||
Publisher: | The Company of Biologists Ltd | ||||
Refereed: | Yes | ||||
Identification Number: | https://doi.org/10.1242/dev.137398 | ||||
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