Four key networks involved in the development of cattle epithelial tissues. A. Cell-To- Cell Signaling and Interaction, Cellular Growth and Proliferation, Hematological System Development and Function. B. Embryonic Development, Organ Development, Organismal Development. C. Cell-To-Cell Signaling and Interaction, Cellular Growth and Proliferation, Nervous System Development and Function. D. Cell cycle, DNA replication, Recombination and Repair, and Cell Morphology. Red dots represent up-regulated genes and green dots represent down-regulated genes.