We know you are in there: conversing with the indigenous gut microbiota.

The vertebrate gut harbors a coevolved consortium of microbes that plays critical roles in the development and health of this organ. Here we discuss recent insights into the microbial-host molecular dialogs that shape the digestive tracts of the model vertebrates, mice and zebrafish, and consider the parallels between vertebrate-microbial mutualisms and the well-studied squid-Vibrio symbiosis.