Final answer:
Sonic Hedgehog (Shh) establishes differential gene expression to control cell differentiation and specialization during development.
Step-by-step explanation:
The differential gene expression in Sonic Hedgehog (Shh) establishes specific developmental processes in cells. Shh is a protein that plays a crucial role in embryonic development and the formation of various organs and tissues. It regulates gene expression by binding to specific receptors on the cell surface, which activates signaling pathways that ultimately lead to the activation or repression of target genes. Through this mechanism, Shh controls the differentiation and specialization of cells during development.