For more than a decade, the field of systems biology has advanced our knowledge of how networks of molecular processes enable cells to perceive their environment and trigger phenotypic changes in response. This view centers on the single cell as a computational unit. However, many biological processes are multicellular in nature and are the product of cell–cell interaction within populations. How do molecular networks at the single-cell level ultimately define collective cell behaviors via social interaction? Understanding how interaction among cells enables the spread of information and leads to dynamic population behaviors is a fundamental problem in biology. A closely related question is how adaptive social interactions evolved in spite of the conflicting selection pressures at the individual and the population levels.
Studies of social interaction in synthetic and natural microbial communities have produced important complementary insights into the social biology of microbes and cell populations in general. This article reviews key work in the emerging field of microbial social evolution and discusses how it contributes to our growing understanding of cell–cell interactions in all multicellular systems.
Social interaction in synthetic and natural microbial communities. (2011) Mol Syst Biol. 7: 483
Social interaction among cells is essential for multicellular complexity. But how do molecular networks within individual cells confer the ability to interact? And how do those same networks evolve from the evolutionary conflict between individual- and population-level interests? Recent studies have dissected social interaction at the molecular level by analyzing both synthetic and natural microbial populations. These studies shed new light on the role of population structure for the evolution of cooperative interactions and revealed novel molecular mechanisms that stabilize cooperation among cells. New understanding of populations is changing our view of microbial processes, such as pathogenesis and antibiotic resistance, and suggests new ways to fight infection by exploiting social interaction. The study of social interaction is also challenging established paradigms in cancer evolution and immune system dynamics. Finding similar patterns in such diverse systems suggests that the same ‘social interaction motifs’ may be general to many cell populations.