If you’ve read enough of the reporting on the completion of genomes, you’ll invariably come across a science writer who has compared the genome to the operating system of the cell. Apparently, a team of researchers from Yale decided to take the metaphor seriously. They built a call graph of the Linux kernel, and compared that to the gene regulation network of the gut bacterium E. coli. Given that the two serve radically different purposes, it should come as no surprise that the layouts look radically different—but the real surprise may be that there are so many intriguing points of comparison.
We’ll take a look at each of the two systems in turn. To create a graph of the E. coli gene regulatory network, the authors divided up genes into three categories. Some genes don't do any regulation; they perform a structural or metabolic function and only receive input from the regulators. These were defined as workhorses, and placed at the foundation of the graph. Other genes participate in regulatory networks, receiving input from their peers, and controlling both workhorses and other regulators—these were termed middle managers. Finally, a few master regulators sit on top of the hierarchy and only regulate other genes.