Honor thy symbionts

TLDR

The intestine hosts a complex, dynamic symbiotic consortium, and its molecular foundations are being uncovered through simplified germ‑free mouse models and comparative microbiota genomics. This study aims to investigate how the intestinal environment shapes microbial and host genome structure and function to reveal coevolutionary mechanisms underlying health. The human–Bacteroides thetaiotaomicron partnership serves as a model illustrating these interactions. Symbionts drive postnatal gut development and host physiology, employing sophisticated strategies to maintain their alliances.

Abstract

Our intestine is the site of an extraordinarily complex and dynamic environmentally transmitted consortial symbiosis. The molecular foundations of beneficial symbiotic host-bacterial relationships in the gut are being revealed in part from studies of simplified models of this ecosystem, where germ-free mice are colonized with specified members of the microbial community, and in part from comparisons of the genomes of members of the intestinal microbiota. The results emphasize the contributions of symbionts to postnatal gut development and host physiology, as well as the remarkable strategies these microorganisms have evolved to sustain their alliances. These points are illustrated by the human- Bacteroides thetaiotaomicron symbiosis. Interdisciplinary studies of the effects of the intestinal environment on genome structure and function should provide important new insights about how microbes and humans have coevolved mutually beneficial relationships and new perspectives about the foundations of our health.