In 1901 TH Morgan proposed in “Regeneration” that pattern formation in amphibian limb
regeneration is a stepwise process. Since, biologist have continued to piece together the
molecular components of this process to better understand the “patterning code” responsible
for regenerate formation. Within this context, several different models have been proposed;
however, all are based on one of two underlying hypotheses. The first is the “morphogen
hypothesis” that dictates that pattern emerges from localized expression of signaling …