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Updated: May 26, 2026
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Grafting of Beads into Developing Chicken Embryo Limbs to Identify Signal Transduction Pathways Affecting Gene Expression
Published on: January 17, 2016
Gradients of signalling in the developing limb.
Matthew Towers1, Lewis Wolpert, Cheryll Tickle
1MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, UK.
Current Opinion in Cell Biology
|December 16, 2011
Summary
Limb development patterns are established by signaling gradients, including Sonic hedgehog for anteroposterior patterning and retinoic acid for proximal patterning. Recent findings also highlight timing mechanisms and Wnt5a/FGF signaling in limb development.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Limb development relies on precise patterning mechanisms.
- Signaling gradients are crucial for establishing positional information.
- Sonic hedgehog (Shh) is a key signaling molecule in limb patterning.
Purpose of the Study:
- To review and synthesize current understanding of signaling gradients in limb development.
- To explore the roles of Sonic hedgehog, retinoic acid, Wnt5a, and FGFs in limb patterning.
- To discuss alternative models for proximo-distal axis specification.
Main Methods:
- Review of recent scientific literature.
- Analysis of experimental evidence for signaling gradients.
- Integration of data on molecular mechanisms in limb development.
Main Results:
- Sonic hedgehog signaling specifies anteroposterior positional information via gradients and timing.
- Retinoic acid gradients are implicated in proximal limb specification.
- Wnt5a and FGF signaling gradients influence limb outgrowth and morphogenesis.
Conclusions:
- Limb patterning involves multiple signaling pathways and mechanisms.
- Both graded signaling and temporal cues contribute to pattern formation.
- Further research is needed to fully elucidate complex limb development processes.
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