bio

Gene regulatory network

A network of genes that switch each other on and off through regulatory proteins (transcription factors), deciding which cell expresses which gene, when, and where. Highly conserved selector genes like the Hox cluster sit at the control nodes of this network, fixing anatomical identity along the head-to-tail axis. Because a whole organ is a network program like this, a single high-level signal can "call" the entire program — building a complete eye — instead of instructing every cell one at a time.