What your microbiome says about you
The trillions of microbes living on and in our bodies could give clues about our background and habits, researchers at Havard University have found.
These mostly-harmless microbes make up our microbiome - the collection of bugs unique to each of us. Babies are born bug-free as they emerge from the sterile environment of the uterus. But they are quickly colonised by the bugs they come into contact with on their way into the world and during their first years of life.
"If you go down to the level of strains - which are variations on an individual bacterial species - at that point we could start to uniquely identify people from the hundreds that we looked at," says Eric Franzosa, research associate at the School of Public Health.
However, as our microbiome changes subtley throughout our lives, it cannot be used as a unique identifier in the same way that our DNA can. However, "The real forensic potential of the microbiome lies is in its ability to tell you something about where that person has been," says Franzosa.
The presence of particular bacteria can be used to predict a person's background. Did an individual, for isntance, grow up in Europe, or America? Have they visited certain countries? Other bacterial strains can also be used to build up a picture of how we live day to day and what we eat. The microbes in the intestine of a vegetarian are very different from those of a meat-eater.
"There are definitely aspects of the human lifestyle that are captured, or represented, in the structure and composition of the microbiome," Franzosa explains. "In addition to forensic identification, it has the potential to do forensic tracking - not just saying who a person is but where they've been and what they've been up to."
Another potential application of microbiome analysis is to personalise medical treatment. One recent study, by Peter Turnbaugh at the University of California San Francisco, showed that a common strain of gut bacterium metabolises a medication normally prescribed for heart conditions.
"If you have the strain that will metabolise that drug, it is less effective than you think it is!" says Franzosa. "So I think there's a real reason people might be interested to know the particular microbes they have on and in their bodies..."
Listen to the interview with Eric Franzosa here: Microbiomes