Highly read on genomebiology.com 7 May—6 June

The rich microbial populations of the human body shift frequently in time — even on a daily basis — with no stable, core group of microbes present at high levels.

Rob Knight at the University of Colorado in Boulder and his colleagues obtained daily microbial samples from the faeces, mouth and palms of two volunteers, over 6 months for one subject and 15 months for the other. The authors sequenced a key genomic region of the bacteria to assess the composition of taxonomic groups. This revealed that the microbial communities are distinct from one body site to the next both in each individual and between individuals. However, only a small proportion of the observed groups persisted across all time points. The authors suggest that factors such as diet, medication and differences in immune-system activity may explain the temporal variations.

Genome Biol. 12, R50 (2011)