User:Jtwsaddress42/Projects/Project 2/Sections/Chapter 6/Topobiology & Epigenesis - Mechanically Linking The Cell & Animal To The Historical Contingencies Of Life

Much of the molecular machinery, and the genes associated with it, that guided and patterned the first animal embryos emerged from the systems of epigenetic behavioral response that had developed in protozoan choanoflagellates. These genes that enable and constrain epigenetic behavioral routines are integrated into a far more ancient genome that organizes and constrains the eukaryotic metabolism and basic physiology. These are the systems linked to the cell surface and its interactions with the environment and other cells. They represent the primary cognitive and behavioral systems of the cell.

Key to the emergence of animals is a transformation of the genetic elements of the epigenetic behavior system into a stable, and relatively consistent, developmental ontology that guides the formation of the animal body plan. It is the acquisition of new repertoires of genes associated with the restructuring of the epigenetic system, along with their respective proteins, transcription factors, and regulatory regions, that eventually results in the emergence stable patterned tissue formation - an absolute prerequisite for animals to emerge.