DNA profiling is a widely known and used method in forensic science. This invention was a breakthrough for investigating criminal cases, since DNA comparisons made it possible to find the perpetrators of crimes and acquit the innocent more quickly and accurately. However, DNA profiling can be used as evidence only if other significant factors support the guilt or innocence of the suspect, since system failures or forensic professionals’ mistakes often lead to inaccurate results of the analysis.
DNA profiling has become one of the most significant discoveries in forensic science as it introduced a new method that allows detectives to solve crimes that could not be resolved earlier. This method appeared in the early 1980s, and the police found many criminals and were able to acquit the innocent by using it (Bright et al., 2019). For example, Sean Hodgson spent 27 years in prison for a murder he did not commit, and comparisons of his blood samples and spot at the crime scene showed that he is innocent (McGuire & Holt, 2017). Therefore, the essence of DNA profiling is to extract a DNA from biological substances left at the crime scene, such as saliva, blood, semen or hair. Types of analysis can vary depending on the availability of samples, suspects and other evidence.
The first advantage of DNA profiling is availability of different methods that are used for analysis, such as PCR, Mitochondrial DNA, STR and Y-chromosome analysis, since they allow scientist to examine even the smallest traces. PCR analysis allows scientists to select and copy data even from several skin cells or hair roots found at the crime scene (Mahajan et al., 2019). STR method evaluates specific areas (loci) that are found on nuclear DNA, which are unique to each person.
Mitochondrial DNA analysis provides data in the absence of nucleated cells, for example, in hair, teeth, or bones that are poorly preserved (Parker & Vronsky, 2017). The y-chromosome analysis only evaluates the male chromosome in cells, which allows the DNA of a suspect to be obtained from his parental relative (Parker & Vronsky 2017). Thus, these methods help to determine the identity of a person by extracting DNA from virtually any form of biological material, although each of them has its drawbacks.
Furthermore, there are various methods of using the obtained DNA, since, in many cases, the police do not have evidence pointing to a specific person. The simplest option is to take a sample from the suspect and compare it with the DNA found at the crime scene. The obtained data also can be compared database by using a computer program that detects matches. The UK’s National DNA Database (NDNAD) was created in 1995 and is still in use today (Amankwaa & McCartney, 2019).
There is also a science of forensic epigenetics that can find the approximate age and gender of the unknown (Vidaki & Kayser, 2018). One of the less accurate, but still valid methods is to determine the DNA of a suspect by taking samples from his or her relatives (Parker & Vronsky, 2017). Consequently, multiple analysis methods provide data that is significant evidence in court.
Another benefit of DNA profiling is that it also used to find the identity of the victim, as well as the link between several crimes. In the first case, DNA profiling is a useful and essential tool if the victim’s body has been detected in the condition that makes it is impossible to identify a person. For example, if the body was mutilated as a result of a car accident or plane crash, fire, or in other circumstances. In this case, experts can take a DNA sample from the surviving tissues and compare them with the data in the database (Machado & Silva, 2019). This aspect is important both for the search for relatives of the deceased person and for the investigation of the crime, since the identity of the victim can indicate suspects.
Moreover, analysis of DNA from different crime scenes can also be useful for determining the connection between them. Such an analysis is necessary as a confirmation of the assumption of the activities of a serial killer, rapist or robber, since similar circumstances of the crimes cannot confidently state that they were committed by the same person. Such an analysis also can help solve unrelated crimes. For example, in Macedonia, a double murder of a married couple happened, and although DNA samples were taken at the crime scene, the offender was not identified.
However, five years later, a burglar suspect was arrested, and his DNA matched the blood left at the crime scene, as well as samples found during a double murder investigation (Jakovski et al., 2017). Consequently, the DNA profiling method helped investigate a crime that could have remained unsolved without this data.
An additional advantage of this method is a psychological effect of DNA profiling on a suspect. If the results of the analysis turned out to be blurry or not weighty enough to act as evidence in court, they can still help to get a confession. Most people are aware of the capabilities of forensic science to determine a person’s identity by fingerprints and DNA, and they believe that the results of the analysis are indisputable evidence (Machado & Silva, 2019). For this reason, if a detective tells the suspect that the DNA at the crime scene coincides with his or her own, perhaps even partially, then this fact may force a person to confess. Thus, it can be noted that DNA profiling also has a psychological impact on solving crime.
However, DNA profiling also has several challenges for its use, the main of which are an inaccurate interpretation of samples, errors in identifying a suspect, and violation of data privacy. Modern technologies have become more sensitive, which is both a positive and negative aspect. Advanced technologies can extract DNA even from the smallest particles; therefore, quite often, samples from a crime scene can have cells not only of the criminal but also of another person who is irrelevant for the case.
According to Press (2019), scientists distinguish various DNA alleys that are displayed by peaks by analysing samples, and these peaks can be several, and they will be of different intensities. For example, on a knife that has become a murder weapon, particles of the epithelium of all the people who have been using it recently but not only the criminal can remain.
Furthermore, DNA can degrade over time or with proper storage and degradation. The samples are highly dependent on the environment in which they are found, the transportation conditions and even the storage status (Press, 2019). Also, if there is no well-qualified personnel to handle the testing and analysis, then there are high chances of the results not being viable. For this reason, the analysis can be distorted and incorrect and lead to an unfair decision. For instance, if the samples were damaged during transportation, then the criminal’s DNA also does not match one from the crime scene. Thus, a test cannot be the primary evidence of someone’s guilt or innocence.
Moreover, even if there is a person’s DNA at the crime scene, he or she is not necessarily guilty. Firstly, a false accusation may arise due to a malfunction in the data system. For example, in 1999, Raymond Easton was accused of a robbery that occurred 200 miles from his residence due to DNA matching; however, Easton had Parkinson’s disease and could not drive (McGuire & Holt, 2017). A match can also be detected due to the error of the expert who conducted the analysis. Such a case occurred in Manchester when test tubes with samples were mixed, and a young man was suspected of rape that occurred 400 km from him (McGuire & Holt, 2017).
Also, even if the DNA analysis was correct, the person could leave his or her mark sooner or later than the crime was committed, or the criminal intentionally left the DNA of another person. Therefore, many circumstances demonstrate that relying on DNA profiling in a court as reliable evidence is a wrong approach.
The collection and storage of DNA data can also cause ethical and legal concerns for citizens. Even if someone is proven innocent legally, his or her DNA information remains in the databases and can later be used for intrusion upon his or her privacy. In addition, in the event of a hacker attack on such a database, information can be stolen or changed to switch the data of the offender with an innocent person. At the same time, the maintenance of such a base by the state and the costs of analysis are financially disadvantageous, since, in Britain, the contribution of DNA profiling to crime detection is insignificant (Amankwaa & McCartney, 2019). Consequently, lawyers need to weigh the need to use confidential information in court.
In conclusion, multiple cases demonstrate that DNA profiling is a useful method for identifying a perpetrator or victim and disclosing crimes. Many effective methods of analysis allow police to find connections for building logical chains and solving even “cold” cases. However, at the same time, this method of analyses has many shortcomings, which are manifested in inaccuracies in determining the identity of suspects due to system failures, external or personal factors of employees. Consequently, DNA profiling can be used as evidence in court, but only if other significant factors support the guilt or innocence of the suspect.
References
Amankwaa, A. O., & Mccartney, C. (2019). The effectiveness of the UK national DNA database. Forensic Science International: Synergy, 1, 45–55.
Bright, J.-A., Kelly, H., Kerr, Z., Mcgovern, C., Taylor, D., & Buckleton, J. S. (2019). The interpretation of forensic DNA profiles: an historical perspective. Journal of the Royal Society of New Zealand, 1–15.
Fernando, M., & Nilanga, U. (2019). Recent Advances in Forensic DNA Analysis: A Review. International Research Journal of Natural and Applied Sciences, 6(6), 18-30.
Jakovski, Z., Ajanovska, R. J., Stankov, A., Poposka, V., Bitoljanu, N., & Belakaposka, V. (2017). The power of forensic DNA data bases in solving crime cases. Forensic Science International: Genetics Supplement Series, 6, 275–276.
Machado, H., & Silva, S. (2019). What influences public views on forensic DNA testing in the criminal field? A scoping review of quantitative evidence. Human Genomics, 13(23), 1–13.
Mahajan V., Padale V., Kudekar, D., More, B., Kulkarni, K. (2019). Hair – a good source of DNA to solve the crime. Archives of Clinical and Biomedical Research, 3(2019), 287-295.
McGuire, M., & Holt, T. J. (2017). The Routledge handbook of technology, crime and justice. London: Routledge.
Parker, R. J., & Vronsky, P. (2017). Forensic analysis and Dna in criminal investigations: including cold cases solved. Paradise, Newfoundland: RJ Parker Publishing.
Press, R. (2019). DNA mixtures: A forensic science explainer. NIST. Web.
Vidaki, A., & Kayser, M. (2018). Recent progress, methods and perspectives in forensic epigenetics. Forensic Science International: Genetics, 37, 180–195.