Meeting Abstract
In surveys of this planet’s microbes, animal guts represent one of the major axes of diversity: communities in animal guts are as different from free-living communities as free-living communities are from one another. Probably not coincidentally, these hosts also evolve, themselves changing as a consequence of their external and internal environments. How do we best understand the diversity of host-associated microbes in light of the evolutionary history of their hosts? Despite tremendous recent investment in microbiome research, our ability to make comparative inferences about host-associated microbiomes commensurate with the scale of our knowledge of host evolution remains strongly constrained by available data. Here we present initial results from a novel dataset of vertebrate distal gut microbiota that expands on previous comparisons by an order of magnitude, comprising over 3000 samples from over 800 tetrapod species. Analysis of changes in microbial diversity both across the broader host phylogeny and in targeted regions of denser taxon sampling reveals the importance of host relationships in explaining patterns of microbial diversity, even with respect to major ecological changes such as host diet. We explore these changes both at the level of microbial community diversity, and, using recently developed statistical and computational techniques, at the level of individual microbial lineages. Finally, we discuss our comparative results in light of recent findings from experimental interventions in model and non-model organismal systems to propose a conceptual model for the coordinated evolution of animals and their gut microbiomes.
