Experimental evolution reveals microbial traits for association with the host gut.

Understanding how microbes adapt to their host is an enduring problem in microbiome ecology, and understanding the microbial traits that allow colonization of the host and increase adaptation to the host environment is of particular interest. In this study, Robinson and colleagues use experimental evolution to demonstrate adaptation of a commensal bacterium to its zebrafish host and describe the changes in phenotype that emerge during this evolutionary process. These results provide insight into the evolutionary problem of host adaptation and demonstrate the utility of simple models for understanding host-microbiome dynamics.