Translation: “Gentlemen, it is the microbes who will have the last word.” —Louis Pasteur, (see: photo at left)
You know the National Geographic documentaries you’ve seen that show a rhino with birds sitting on its back? According to the African Wildlife Federation, his feathered friends are called "oxpeckers," also known as tick birds. The oxpeckers are actually nibbling on all sorts of bugs. They also feast on the blood from sores and, even though they obstruct sores from healing, they also help to warn the rhino of danger. This is what is referred to as a symbiotic relationship.
Humans also have their own riders. They are organisms called “microbes.” Microbes live on us by the billions. Scientists have examined six different people’s forearms and found more than 240 distinct microbes hanging on. The skin’s ecosystem, for want of a better term, is as unique as a person's wardrobe. While there is some overlap in microbe types between people, in the study, microbe types are still thought of as being distinct and unique to each individual. (As an aside, what is interesting is that a change in soap, laundry detergent, or even the fabric we wear has an affect on the “skin flora,” which is what scientists really call the microbes.)
Skin Flora and Forensic Science
This past spring, there were some reports about how this phenomenon could be used for identification purposes through a process called bacterial fingerprinting. Scientists in Colorado are surmising that one day, bacteria fingerprinting may find itself in the courtroom. Noah Fierer of the University of Colorado, in Boulder, is one of the scientists who studies the bacteria that live on skin, and he says, "We leave this trail of bacteria everywhere we go, and the idea was could we use this trail to identify who had touched a given object or surface.”
According to U.S. News and World Report, the team used powerful gene sequencing techniques to conduct the analysis. The process involved examining a specific bacterial gene from each sample. The gene, called the 16S ribosomal RNA gene, is a useful tool for identifying bacterial species. All cells carry a 16S gene, but the gene changes just enough over time to distinguish one species from another. Each bacterial sample is capable of generating a unique “signature” of all the bacteria that are present. Comparing those signatures, which derived from algorithms developed by Rob Knight, another member of the Boulder team, can identify two microbial communities as being closely related. In this case, the 16S profiles from the fingers of the keyboard users closely matched the 16S profiles from each user’s keyboard.
Nathaniel Burney, a white-collar criminal defense lawyer in New York, is not getting excited. He says, "...the media took this modest finding and blew it way out of proportion. The study’s authors insist that the project 'is still in its preliminary stages.' The media make it sound like we’ll be seeing this stuff in court before we know it. The fact is that using microbial DNA to link a suspect to a crime scene is not going to be a reality any time soon, if ever." Burney says the uniqueness of your bacteria being truly singular is very much an open question. And he points out that bacteria is functionally different on different parts of the body, so coming up with isolated bacterium would be a nightmare for comparison.
Still, it’s an interesting idea considering the possibility; because like that rhino, we all have a symbiotic relationship with the bacteria riding on our own skins.