HYBRID NICHE-NEUTRAL MODEL FOR THE GUT MICROBIOTA

The gut microbiota is a complex ecosystem integrated in the human body. Its relevance in the host's health is by now well established. For this reason, several studies are currently focusing their attention on its composition and ecological properties. Among such properties, biodiversity is indeed a key one, being an indicator of the health of an ecosystem. Despite that, the choice of the optimal metric to measure biodiversity in an effective way is still a matter of debate. Here, we discuss the main approaches proposed for this purpose, considering both classical statistical indices and model-based ones. We describe the relevance of the Relative Species Abundance distribution and the main probabilistic and ecological models that have been used to fit it. Finally, we report results obtained on the gut microbiota of three groups of subjects for which differences are expected: healthy Italian adults, Down Syndrome Italian adults, and Tanzanian Hadza hunter-gathers. Our results show the utility of considering a hybrid niche-neutral model to evaluate the biodiversity of this meaningful ecosystem.