In the crime scene of the future, forensic analysts might not be basing their investigations solely on traces of DNA and fingerprints, but also a criminal's microbiome.
In a paper published today in the journal PeerJ, researchers from Oregon University describe how each person possesses a unique "microbial cloud signature." This is the millions of bacteria that every human's microbiome emits into the surrounding air. Think of it as a kind of aura in the shape of a invisible bacterial cluster that forms a halo around our bodies.
The researchers investigated the connection that this puff of microbes has with the surrounding air.
"What we were trying to do was to take the knowledge that we have about the human microbiome and microbiology and that we've begun to discover in the built environment, and understand how those two interact," Adam Altrichter, a research assistant at the University of Oregon's Biology and Built Environment Center, told me over the phone. "How does an individual contribute to the microbiology inside a building?"
The human microbiome (all the microbes that live in our body) might not sound that exciting. But lately, research has explored how and if it plays a pretty big part in our health and happiness. What the researchers at Oregon University want to explore is if it leaves a detectable trace in the air around us, and if our unique microbiome clouds can act like data sets that harbour information on where we've been before.
For their study, the researchers placed 11 different people in tank tops and shorts in a sanitized experimental chamber, and collected and sequenced their microbial cloud data. They found that most of the participants could be identified within four hours by the unique cocktail of microbiome bacteria (Streptococcus, which is found in people's mouths, and Propionibacterium and Corynebacterium, which is found on people's skin) and air. Usually it's a unique of bacteria and air that makes up each and everyone of our microbial cloud datasets.
Altrichter told me that in the future, the researchers wanted to explore how their current findings would be applicable in a real world setting, where you didn't have sanitized people sitting in chambers, but more like at desks and in bustling crowds.
"How does an individual contribute to the microbiology inside a building?"
"We spend upwards of 90 percent of our time indoors, so we know that we're contributing a great deal to the microbiology of the buildings around us," Altrichter told me. "So we have questions on how far this microbial cloud might spread, how persistent it is over time, if you have multiple people in the same room at the same time, could you distinguish individuals from each other?"
For the moment, Altrichter admits that his musings are speculative. But the simultaneously exciting and dystopian possibilities of each of our microbial clouds acting as invisible fingerprints remain.
"We're thinking of the more speculative things that we can apply this to. If you have individuals who were in a unique soil environment, of if there was a building with a certain microbial signature and maybe the individual acquired some of this while they were in the building, you might be able to find clues of this in their microbial cloud signature," said Altrichter.
The research is still in its infancy, but does it hint at a future where you might have to find a way to encrypt your microbial cloud data as much as your online transactions?