One truth in forensic DNA testing is that you must have a sample to test. That, of course, should be self-evident. But sometimes crime scene DNA isn't readily available. There are no blood or semen stains on the floor or bed sheets or any location where they could be easily sampled. What's the crime lab to do?
New methods are under development that allow for extracting useable DNA from some unusual places, even dirt. GEMBE (gradient elution moving boundary electrophoresis) grabs DNA hidden in the dirt by employing a molecular "tug-of-war." Cool.
For more about DNA sampling and testing, grab a copy of my updated, 2nd Edition of FORENSICS FOR DUMMIES.
