Mycoplasmas and the Minimal Genome Concept

Abstract

The ultimate goal of biochemistry and molecular biology is the complete description of biological systems in terms of the laws of chemistry and physics. Consequently the mycoplasmas attracted the attention of biologists because of their small size and apparent simplicity, just as the hydrogen atom provided the simplest model for the development of physicists’ theories of the atom. But, while hydrogen atoms are primitive, fusing within the interiors of stars to form the heavier elements, the mycoplasmas are simple for quite the opposite reason. They evolved from complex bacteria through the loss of functions that are unnecessary in their habitats as parasites on multicellular organisms. This evolution has proceeded far down the path toward distilling a minimal set of essential cellular genes.