Building Communities from the Bottom Up

Many challenges in synthetic biology involve the interaction of myriad cell types, both engineered and natural. Microbial communities represent another example of complex, interacting groups of cells, with the function of the community largely determined by these interactions. An exciting opportunity exists to discern the rules governing community assembly and function. In this talk I will describe our recent experimental efforts to develop a bottom-up approach to understanding the dynamics of microbial communities. We have begun by quantifying the network of pairwise competitive outcomes among species within a model microbial community. We find that simple assembly rules incorporating just these pairwise competitive outcomes are surprisingly successful in predicting the outcome of multi-species competition in multiple environments as well as within the gut of the worm, indicating that higher-order interactions among species can often be neglected. These results are a first step towards a bottom-up approach of predicting the emergent behavior within complex multi-species communities.