A new method of forensic identification, based on the bacteria that populate a person’s skin, has the potential to bolster cases where conventional DNA and other more traditional forms of identification cannot be obtained.
“It's a small, emerging sector of the technology,” says Professor Tiffany Roy of Palm Beach Atlantic University. “The idea behind it is that each person has a unique mixture of bacteria on their skin. When they handle an item routinely there would be a transfer of their unique signature of different types of bacteria that are transferred to the item. That can be then swabbed and, if conventional DNA testing doesn’t work out then they can perform microbial DNA testing which will give a microbial fingerprint.”
The uniqueness of microbial DNA is the result of a number of factors, says Professor Roy: “The soaps that you use when you bathe, the frequency with which you bath, the foods that you eat, your level of nutrition – all of those things affect which bacteria thrive and grow in which concentration on your skin. It is affected by all of your environmental interactions and also your own body chemistry. Everybody’s body chemistry is slightly different, their metabolism is different, it can be affected by medications that they might be taking, genetic diseases and variations – all of those things will alter the composition of the bacteria that is on a person’s skin.”