The functional composition of living machines as a design principle for artificial organisms

How similar are the engineering principles of artificial and natural machines? One way to approach this question is to compare in detail the basic functional components of living cells and human-made machines. Here, we provide some basic material for such a comparison, based on the analysis of functions for a few thousand protein molecules, the most versatile functional components of living cells. The composition of the genomes of four best known model organisms is analyzed and three major classes of molecular functions are defined: energy-, information- and communication-related. It is interesting that at the expense of the other two categories, communication-related coding potential has increased in relative numbers during evolution, and the progression from prokaryotes to eukaryotes and from unicellular to multi-cellular organisms. Based on the currently available data, 42% of the four genomes codes for energy-related proteins, 37% for information-related proteins, and finally the rest 21% for communication-related proteins, on average. This subdivision, and future refinements thereof, can form a design principle for the construction of computational models of genomes and organisms and, ultimately, the design and fabrication of artificial organisms.