Spatial and temporal variability of the human microbiota.

The knowledge that our bodies are home to microbes is not new; van Leeuwenhoek first saw the microbes of the mouth and gut over three centuries ago. However, next generation sequencing technologies are enabling us to characterize our microbial consortia on an unprecedented scale, and are providing new insights into the range of variability of our microbiota and their contributions to our health. The microbiota far outnumber the human component of our selves, with 10 times more cells and at least 100 times more genes. Moreover, while individuals share over 99.9% of their human genome sequence, there are vast differences in the microbiome (the collection of genes of our associated microbes). This raises the question of the extent to which our microbial community determines our human physiological responses and susceptibility to disease. In order to develop technologies that allow us to manipulate the microbiome to improve health we must first understand the factors that influence spatial and temporal variation, stability in response to perturbation, and conditions that induce community-wide changes.