Microbiome interactions shape host fitness

Synopsis

Each person has a unique gut microbiome composition that is stable over time, like a fingerprint. Different compositions are associated with different disease risks. Therefore, it is crucial to understand how an individual's unique gut flora is determined. With hundreds of species, vertebrate guts are difficult to dissect experimentally. My lab developed the fruit fly gut microbiome as a model because of its natural low diversity. We find that colonization works like a lottery, with a different per-cell odds of gut colonization associated with each individual species of bacterium. When multiple species of bacteria colonize, strong priority effects occur, meaning that first arriving species significantly influence later arrivals. Thus, two individuals exposed to the same two species in reversed orders can end up with different microbiome compositions, giving them different lifespan and fecundity. I will present data and theory measuring colonization and the impact on host fitness.