Spiraling complexity, robustness, and fragility in biology

As biologists delve deeper into genomics, gene regulation and subcellular interactions, the networks that regulate cell function can sometimes appear wildly and gratuitously elaborate, since it is known that enormous complexity is not necessary for basic cellular survival and function. Minimal cellular life is thought to require about ~300 genes, yet even E. coli have ~4000 genes. Gene knockout studies of E.coli confirm that about 90% of its genes are not individually essential for viability in the laboratory. Recall that in our idealized allometry wind tunnel laboratory, almost the entire 150,000 element 777 “aeronome” can be simultaneously knocked out without exhibiting a phenotype. These observations are clues that the reason for the “excess” complexity is not merely redundancy, but the presence of complex regulatory networks that effect robustness but not minimal functionality.