How Is DNA Collected?

With the huge advances over the past 25 years, DNA extraction and results are critical and reliable sources of information. Not only used for paternity testing, DNA collection is useful for a large number of purposes from solving crimes to genetic counseling. The methods used to collect DNA also vary depending on whether the DNA is collected from a crime scene or from a more medically sterile condition with a live subject.

Crime scene collection

At a crime scene, there are several routes a police officer or crime scene investigator can take to collect DNA evidence. New technology allows investigators to gather DNA from relatively small samples of bodily fluids. For instance, if a suspect drank a glass of water at the crime scene, a crime scene technician can often obtain a DNA sample from the saliva on the glass. In some cases, it is even possible to obtain DNA from skin or hair left behind at the scene. In a crime scene scenario, collecting "elimination samples" is also common: An elimination sample is collected to eliminate other possible suspects. Therefore, the astute technician and investigator examine the environment closely for all possibilities of DNA left at the scene.

Medical collection

Medical collection of DNA is often far easier than crime scene collection since the subject is usually willing to cooperate and the environment is usually sterile. The most straightforward method for collecting DNA for medical purposes is to take a saliva swab from the subject's cheek. If that is unsuitable for some reason, a DNA sample is also easily obtained by drawing some of the subject's blood. Obviously, It is much better to collect DNA when the person agrees to testing under medically supervised conditions.

DNA collection technology has advanced tremendously in the past 25 years, especially in the area of crime scene collections. Modern collection methods are more reliable and less prone to cross-contamination or other problems. Given these advances, both medical and nonmedical uses for DNA are sure to increase over time.