Can DNA still be detected if there is any sexual assaults happens?
Rape, something we hear it VERY frequently on the news that even babies do get raped! And sometimes it’s very hard to identify the person who committed the crime if they have cleared the place leaving no evidences behind. This make us hard to find the rapist who did it. So the only thing you could do is not to wash yourself and the clothes that you have worn on that day of the incident happened thinking that DNA can be easily removed if we them washed away. But hey here is a trick….
There was a study using serological and genetic properties of washed and unwashed stains on fabrics, researchers can learn more about the persistence of sperm and saliva.
- For semen, detection with the naked eye or under a forensic light source, acid phosphatase (AP) testing, PSA testing and microscopy analysis were done on stains washed up to six times. The stains with two different methods (swabbing and cutting) to compare the DNA quantities and the resulting genetics profiles.
- For saliva, detection under a forensic light source and α-amylase testing were done on stains washed up to three times. Saliva stains were sampled by cutting for DNA analysis.
Throughout all experiments, there were five donors, three different washing machines and two detergents were assessed. Results show that some semen stains washed six times can still be detected using a combination of forensic light source and PSA testing, and that most will generate a complete genetic profile when sampled by cutting.
Swabbing collected DNA in quantities sufficient for amplification only from unwashed semen stains. Saliva stains could hardly be detected through forensic light source and α-amylase testing after a single wash, but it was still possible to generate complete genetic profiles, even after three washes. The study shows that it is possible to obtain interpretable DNA results on washed semen and saliva stains. There are some insights to optimize stain detection and sampling strategies according to the circumstances of the case and whether the forensic biologist is looking for an unwashed stain (ex: sexual assault in a hotel room) or a stain that may have been washed multiple times (ex: underwear from a child who reported a sexual assault several days after the event).
So let’s spread this to everyone or maybe we could develop the similar protocol to detect the DNA and find the culprit easily.
Source : CLOTHING AND BEDDING FROM SEXUAL ASSAULTS CASES: IS DNA ANALYSIS STILL RELEVANT AFTER LAUNDERING? Sarah Noël, Karine Lagacé, Sylvain Raymond, Magali Loyer, Roxanne Landry, Josiane Larose, Sarah Bourgoin, Marie-Christine Théberge, Alphonse Ligondé, Christine Jolicoeur, Diane Séguin, Laboratoire de sciences judiciaires et de médecine légale
