Editor's choice: human microbiome

Increasingly, we recognise the importance of the microbiome – the bacterial (and other) flora that lives within us, sometimes in conflict, often in symbiosis, always interacting. Whether the microbiome changes drive changes in our health, or vice versa, is not often known. But figuring out what a healthy microbiome looks like or how it can evolve in the time of disease can help us better understand the minutiae of these interactions.