Contribution of neutral processes to microbial community assembly over host development

Background/Question/Methods

The microorganisms that reside on and inside humans and other animal hosts are remarkable, not only because of their importance to host health and development, but because they must assemble into complex communities de novo in every new hatchling or infant. This makes host-associated microbial communities interesting systems in which to study the dynamics of community assembly. As such, we explored the microbial communities associated with the developing zebrafish, Danio rerio.

Results/Conclusions

Using neutral models we found that as hosts develop from larvae to adults, the relative importance of neutral processes decreases and that communities become increasingly phylogenetically clustered. This suggests the importance of filtering by the host environment increases as hosts mature and accumulate developmental changes. We also show that these trends are mirrored, at least in part, in humans. Finally, we provide examples of how such a framework can be used to isolate the roles of specific host selection factors as well as to identify aberrant microorganisms and host systems undergoing unique assembly dynamics. Ultimately, understanding the processes responsible for the assembly of these host associated communities will not only inform how we might alter and exploit them to improve human health, but will also inform our understanding of how complex communities form in general.