Joel Sachs: UCR

Beneficial bacteria improve our health and are crucial to crops plants and fodder animals. However, symbiosis is evolutionarily unstable: harmful mutants can invade symbiont populations and cause cooperation to collapse. My research encompasses both theoretical and empirical work on the evolution and maintenance of bacterial symbioses with eukaryotes. My theoretical work seeks to understand how symbiotic cooperation is maintained and to predict the conditions in which exploitative / pathogenic mutants invade. This theory has important applications for medicine (maintenance of gut, oral flora symbioses), agriculture (optimization of nitrogen fixing symbioses) and bio-production (e.g., selection of bacteria to perform biochemical reactions). My empirical interests are broad and I use a combination of experimental, molecular and genomic approaches. Currently, there are two overlapping research programs within my lab. One approach employs wet-lab techniques to study the evolution and breakdown of nitrogen-fixing plant symbioses (rhizobia). Our second and newer research program is mainly bioinformatic and investigates the origins and stability of bacterial symbioses writ large (e.g. across whole bacterial lineages) and thus over deep evolutionary time.