All about DNA evidence

DNA evidence is the data obtained after DNA analysis is done from collected biological matter. DNA evidence is used during forensic investigations involving crime, paternity and ancestry. The use of DNA evidence utilises information contained in biological material collected from an individual or a crime scene to ascertain relationship. For DNA to be used as evidence, it has to undergo a process known as DNA profiling/typing.

What is DNA?

DNA is the genetic identity that differentiates every individual from the rest. The genetic make-up of a person consist of double helix proteins molecules unique to that person. Each cell of the body has a complete profile of the genetic make-up of a person - determined from the arrangement of the DNA molecules. Parents and offspring share some similarity, but not whole resemblance of the genetic make-up - the reason why it is used for paternity testing. Due to this uniqueness, DNA can be used as evidence against people suspected to be involved in crime.

Preparation of DNA evidence

For DNA to be used as evidence in any case mentioned above, the arrangement of the DNA molecules must be ascertained. The technique used to profile the DNA is called DNA typing and it gives the precise information contained in the collected samples. Once DNA profiling is done on samples collected from a crime scene, another DNA profile must be done on the actual suspected person. Any biological matter can be drawn from the suspect, for example, hair, skin cells, finger nails, blood and so on. From the suspect, the samples also undergo the same DNA analysis and profiling as that of the samples from crime scene. Comparisons are done between the two profiles and if similarly is ascertained, the suspect is held liable.

How to collect DNA evidence

DNA evidence must not be of forensic investigations alone. Fathers who suspect the paternity of their children can have blood drawn from them and taken to the lab for testing. Forensic DNA is collected from crime scenes. Hair strands, sexual fluids, skin cells and blood spots can be collected and reserved as DNA evidence. DNA can also be collected from immigrants to ascertain their ancestry origins. This is because genetic information is passed from generation to generation, and there are genes unique to only certain types of people.