DNA can be sequenced - you can get the exact base pair sequence. Again, this can tell you about the persons genetic make up... different versions of different genes they have, etc. In an experimental lab, it can verify that you are working with the DNA that you think you are. DNA can be put through chromation immunoprecipitation assays (ChIP) In this test, you are looking for a protein that bind to a particular sequence of DNA.
More in Post Traumatic Stress. Eye movement desensitization and reprocessing (EMDR) is a treatment for PTSD as well as other mental health conditions (see below). The treatment brings together your traumatic memories and positive thoughts and beliefs to help reduce the distress stemming from your traumatic event.
This processing technique can bring quick and lasting relief for many types of emotional distress. EMDR uses a natural function of the body, Rapid Eye Movement (REM), as its basis. The human mind uses REM during sleep time to help it process daily emotional experiences.