You are outnumbered by a factor of 10 to one, by forces you
cannot see. Your body has around ten trillion cells, but it’s
also home to a hundred trillion bacteria. For every gene in your
genome, there are 100 bacterial ones. Most of these are found
the dark, dank environment of your bowel but their incredible
diversity is being brought to the surface. Say hello to the gut
metagenome. Together with a team of international scientists,
Junjie Qin and Ruiqiang Li from BGI-Shenzen had the unenviable
task of studying the bacteria from the faeces of 124 Europeans.
They used a formidable and audacious technique called
metagenomics, which analyses all the genetic material in a
sample, without bothering to culture the individual species
first. It’s a shoot-first-ask-questions-later method that
captures all the data and lets other programmes sort out the
mess. Stool samples from 33 people have already been analysed in
this way, but Qin and Li managed to sequence almost 200 times as
much DNA. Brace yourself for some big