Pattern formation and developmental mechanisms. Converging views of diverging pathways

One of the great themes in modern developmental biology is the underlying unity of developmental mechanisms that govern pattern formation in all animals. Superficially, many classical paradigms of developmental patterning appear to be quite different. In the last decade, these classical experimental systems have been found to be based upon similar signaling pathways and regulatory hierarchies. For example, anterior/posterior patterning in all animals are governed by the genes in the Hox cluster(s), and axis formation in the frog egg, limb development and pattern formation in insect wings are established by common signaling pathways. There has been great joy in discovering the unity in mechanisms for developmental patterning and there is also great power in knowing that similar types of genetic pathways regulate patterning in all animals