An awful lot of microbes could reveal a great deal about the human body

THIS year teams of dedicated researchers working on the new Human Microbiome Project (HMP) began collecting faeces samples and swabs from the vagina, mouth, nose and skin of 250 volunteers. They are the modern equivalent of Victorian bug hunters, classifying new species in uncharted territory.

But rather than using nets and chloroform, their tools are the high-speed gene-sequencing machines developed for the Human Genome Project. And their task dwarfs the genome project: with perhaps 1,000 species under investigation, the number of bacterial genes could amount to 200,000, compared with 20,000 human ones. HMP is a $100m American project funded by the National Institutes of Health. Its aim is not only to classify the microbial inhabitants of humans, but also to identify where they live and what strains people have in common. ...