“The human microbiota is a fundamental component of what it means to be human,” says David Relman in a recent JAMA opinion piece. In this article, Relman gives a picture of the importance of the human microbiota in health and a brief history of how scientists have measured it.
Relman names body site as one of the strongest determinants of microbiome diversity variation, perhaps because of the different selective pressures at each site. He says that by learning more about the features of microbiota structure and function in each “ecological zone” of the human body (including the gut), scientists may be able to detect early markers of local disease.
Relman cites evidence that small molecules may promote stability of microbial communities by mediating interactions among community members. Some stable states are associated with health, and others with disease. Furthermore, communities that lack resilience — i.e. the ability of a complex system to return to its original structure following a stress/challenge — could be vulnerable to environmental factors such as antibiotics. To better understand these dynamics, Relman calls for studies with more dense temporal and spatial sampling of microbial communities.