There are cases where the value of genetic profiling changes depending on the way the genetic material was deposited onto a surface or the environment it was situated. To determine the above parameters, alongside detecting human DNA, we can look into the DNA of bacteria that are found together. In this way, it is possible to determine e.g. which part of the body came in contact with the surface and/or which environment, depending on the type of micro-organisms detected.

This new capability has significantly contributed to investigations of rape and sexual assault cases involving use of objects. If the victim is detected on these objects, determining the source of bacteria colocalising with the victim’s DNA, i.e. if they are bacteria from vaginal/anal flora or skin bacteria or if they are bacteria associated with a particular environment (e.g. soil or water), can contribute significantly to solving the case.