Understanding the genetic fingerprint techniques used in forensic analysis rarely departs from theoretical explanations, supplemented with images of results. Real experiments on such topics are not easily available and offer little chance for repeated and varied tests.
A virtual laboratory has been implemented with a setup for paternity tests, employing multiplex PCR on a subset of STR markers taken from the CODIS system. The user is presented with DNA samples from a child, his/her mother and 4 candidate fathers. First, the system guides the user through acquisition of samples, primers and other reagents. Then, the user must process the samples, using virtual pipette and tubes, to set up PCR mixes on which, if properly prepared, the STRs will be amplified. After simulated electrophoresis, the resulting band patterns must be interpreted to identify which one, if any, of the candidates is the real father.
The virtual lab offers guidance during the procedure, but results will vary according to the actual operations followed, therefore providing a realistic scenario and promoting the execution of subsequent experiments to clarify results. Samples are randomized, so the result cannot be anticipated; there is also a chance that none of the 4 candidates is the father.
The simulation is implemented as a web application using just DHTML, so it can be run in nearly any computer, both locally and on-line. The application is offered under a Creative Commons licence.