DNA technology is one of the most reliable and accurate ways of drilling deeper into the truth when establishing a connection between evidence and a source. The technology has been accepted by the public and reinforced as the “gold standard” when it comes to justice.
It seems that no another forensic technique appears to beat DNA in presenting things the way they are. You will agree with me that DNA test results act as the most powerful propellant in our courtrooms today.
However, you will be shocked how this costly and time-intensive technology can lead to false prosecution among other heartbreaking cases.
The ugly truth is that this top-notch forensic technique that is meant to wipe away subjectivity in forensics has its problems too.
The Complex Mixture Confusion
DNA profiling is like a stack of transparent films where the audience is expected to determine the number of the main characters. This is why more strict standards are required in the forensic science to eliminate the subjectivity associated with this technique.
Analyzing the complex mixtures is a pretty difficult job that makes everything wrong when it goes wrong. We all have genetic codes or alleles that differ from one person to another. What complicates the analysis is the fact that the number of alleles in a sample doubles or triples as the number of contributors increases. This math gets complicated and often leads to errors.
The fact that the analyst has to compare the alleles from all the contributors makes it more difficult as some parts may be missing or degraded. Therefore, how accurate or not the reading of complex mixtures gets is indeed a subjective topic. Several analysts arrive at flawed conclusions and end up landing some innocent victims in jail.
Errors In Sample Labeling Or Identification
I know this may sound like the highest level of incompetency but the sad truth is that it happens. Some DNA technicians are so careless that they cannot manage to obtain consistent results from the same person. This occurs when DNA analysts confuse the test samples and label them as though they were from two separate individuals.
Several convictions occur due to this stupid mistake if I may say. There are some cases where further analysis of DNA results shown inconsistency even when the blood, semen, and saliva samples were from the same person.
This is perhaps one of the most common shortfalls of DNA testing. There are instances where DNA got transferred to several areas in a crime scene. When we touch, do laundry and shake hands with each other, migration of cells from one person to another or between objects occurs.
One of the reasons as to why several crime cases have failed to meet justice is due to contamination in the collection of DNA samples. The fact that our bodies shade cells differently even complicates the analysis. What this means is that the strongest DNA profile doesn’t necessarily match to the contributor that came into contact with the sample the most.
This is one of the greatest mishaps in the crime scene as a witness may end up in conviction just because the strongest DNA profile was his or her match. Contamination Hazard can, however, can be avoided or reduced with proper care and the right techniques put in place.
There is always a substantial probability of finding a match especially in a large database such as the FBI’s National DNA Index System, the store of millions of profiles. Statistically, there is a once-in-7000 chance of DNA match. In a case where independence is jeopardized, especially in criminal cases, there is room for biased conclusions when one side of the court proceedings is likely to profit from the final verdict.
The Either Right Result Or No Results Rhetoric
Believe it or not, not every DNA test carried out leaves the analyst with a full profile. There is a higher chance of obtaining partial profiles especially when there are breaks or drops in the alleles at a particular locus.
This may happen when there is tampering with the evidence or as a result of contamination. In that case, determining the genotype at every locus becomes impossible.
Several individuals have been freed or wrongfully convicted as a consequence of an inconclusive result. The result or no result rhetoric puts the credibility of the most trusted forensic technique to test.
Misinterpretation Of Results
In most cases, carelessness and mistaken identity in the lab cause distortion of DNA results. Some technical problems in the lab can also be the reason. Thanks to modern policies that allow criminalized individuals to access DNA retesting. Several people have regained their freedom after being falsely incriminated due to incorrect interpretation of results.
Planting Of Evidence
This has always been a bone to chew for crime specialists. Planting biological evidence in the crime scene has been a persistent practice in the history of crime. The truth of the matter is that a convicted person could be innocent even after a DNA match is established.
This is why people whose profiles are in the government database risk false incrimination. It would be easier tracing a DNA match to their profile.