Understanding DNA transfer
If you have ever watched a true crime special on TV or even just listened to court proceedings, you might get the impression that DNA evidence is the be all end all in proving a defendant’s guilt. DNA–the genetic material contained in each of a person’s cells–can be used to determine certain details in a criminal case, but according to scientific experts, it is far from infallible. There are several things to take into consideration when it comes to the role of DNA in criminal prosecutions.
Secondary DNA transfer
Secondary DNA transfer can occur when two people engage in intermediary contact. If, for example, you shake hands with somebody and they then touch a surface, your DNA could reasonably be found on the surface even though you never touched it and may have never been in the building. This is one way in which DNA evidence may be unreliable, and it is also indication of how easily DNA can be used against innocent people.
Lab-generated touch DNA
Unfortunately, many laboratories have developed the technology and resources to take trace remnants of DNA material and reconstruct a full genetic profile. This is called touch DNA, and it is problematic for obvious reasons: if only a trace amount of DNA is found, it could very likely be the result of secondary DNA transfer. A full DNA profile does not necessarily prove that the subject was actually at the scene of the crime.
Lab error in processing DNA
In addition to a lab’s ability to create a genetic profile from touch DNA, a lab can complicate DNA results because of the potential for human error. Indeed, labs are tasked with a vital job in testing DNA samples, but that does not mean that staff is impervious to making mistakes. A simple mix-up can generate false results and compromise the proceedings of a criminal case.
Intentional DNA transfer
In some instances, DNA transfer is no accident or error. Because it is so easily transferred and potentially manipulated, DNA can be intentionally employed to make it appear as though somebody was at the scene of a crime. Once it has been detected, though, there is often no clear way to determine whether it was placed there nefariously or if it naturally occurred.
These are just a few of the many legal complexities surrounding DNA evidence. If you are involved in a case that includes DNA, reach out to a lawyer for the representation and guidance you will need.