Signalling pathways that act coordinately to control vertebrate limb development.

Basic metabolic panel signalling is embedded within a larger network of signalling pathways that act coordinately to control vertebrate limb development. The complex interactions between different signalling pathways are difficult to dissect and the focus of ongoing research. A researcher that you collaborate with is currently working on the sonic-hedgehog signalling pathway. Although the sonic-hedgehog (Shh) ligand is not expressed in the developing vertebrate limb, the researcher has hypothesised that active sonic-hedgehog signalling could induce gremlin expression in interdigital cells.

Describe an experiment using chick or duck embryos that could be used to test this hypothesis.