By Nicola Jones of Nature magazine

The non-profit programme MyMicrobes, launched today, is inviting people to have their gut bacteria sequenced for about €1,500 (2,100). Acting as both social network and DNA database, the website offers a place for people to share diet tips, stories and gastrointestinal woes with one another. In exchange, researchers hope to gather a wealth of data about the bacteria living in people's guts.

The same team of researchers showed earlier this year that people fall into one of three groups, or 'enterotypes', when it comes to the genetics of their gut bacteria (see 'Gut study divides people into three types').

"I got between 50 and 100 e-mails from regular people having problems with the stomach or diarrhoea and wondering if we can help them," says co-author Peer Bork, a biochemist at the European Molecular Biology Laboratory in Heidelberg, Germany. "They were long e-mails. There must be a lot of frustrated people out there." That response, he says, spurred the creation of MyMicrobes.

So far, the team has found links between certain gut-specific genetic markers and obesity and other diseases. And they suspect that gut enterotypes might affect how people react to different drugs and diets. Bork says he was visited by some practitioners of traditional Chinese medicine who wondered whether the three enterotypes might explain the three different response groups they see with herbal remedies, Bork says. "They're convinced it's connected. I have my doubts that it's so simple, but there are lots of thoughts along these lines."

The group has been careful not to make promises to project participants. The research is still in its infancy, and there is no proven link between enterotypes and disease remedies. But the researchers hope the project will provide a bounty of data while helping volunteers connect with one another. Participants will have access to their own data, but all public results will be anonymous.

Gutsy endeavour

After registering on the site, study participants are shipped a package of information and a stool-sample kit. They'll mail the samples back to a lab in Paris where the DNA is extracted and sent to Bork's lab in Heidelberg for sequencing.

The actual cost of sequencing the gut genome is about €2,000 per person, says Bork. Participants are asked to contribute at least €1,451 of that cost, plus shipping. That's more expensive than, say, the $207 it costs to have some crucial parts of your personal genome sequenced by 23andMe, a genomics company in Mountain View, California.

The cost difference is due, in part, to the smaller scale of the MyMicrobes operation, and in part to the size of the bacterial genome, which Bork says contains around 5 billion letters of DNA, compared to the 3.3 billion in the human genome.

23andMe has no plans to pursue faecal sample sequencing, although the company has considered it. "We talk about dozens of directions we might take beyond genotyping. That is one [direction] that has intrigued us," says senior researcher Joanna Mountain.

Mountain wonders whether data from the MyMicrobes project will continue to indicate three clear enterotypes as more and more gut genomes are sequenced.

Bork says that around 100 people have registered their interest in the project, though not all of them have committed to the hefty price tag. The researchers estimate that they will need about 5,000 participants for the site and the study to be meaningful. "It requires a critical number of participants. Just like competitors of Facebook, we might fail to get that critical mass," says Bork.

This article is reproduced with permission from the magazine Nature. The article was first published on September 8, 2011.