How to Use DNA Analysis in Court

DNA Analysis
Abstract
This paper discusses the history of DNA analysis, how it came about, how it was first used in a criminal case, and some of the limitations of DNA analysis as shown by later criminal cases. It looks at how DNA analysis is currently used today, including a recent criminal investigation in Europe in which DNA analysis played a crucial role, and provides a description of the various directions that DNA analysis could be taken in the future in the field of forensics. The paper concludes with a summation of the main points of the paper.
Keywords: dna analysis, dna profiling, dna forensics, dna criminal justice history
Introduction
DNA analysis, also known as DNA fingerprinting in the beginning, came about in the latter half of the 20th century through breakthroughs in scientific investigation. It has been used in forensics ever since and is defined as “comparison of the DNA in a person’s nucleated cells with that identified in biological matter found at the scene of a crime or with the DNA of another person for the purpose of identification or exclusion” (Roewer, 2013). DNA analysis is now a common tool of criminal justice and is used in forensics to help identify suspects and in some cases to clear others. This paper will provide the history of DNA analysis, how it is used today, and what the future holds in store for this area as a tool for the field of criminal justice.
History
Alec Jeffreys made the first discovery of the method of DNA analysis in the mid-1980s in the UK (Jeffreys, Wilson & Thein, 1985). Jeffreys was working on identifying “simple tandem-repetitive regions of DNA (or ‘minisatellites’)” that occurred in the human genome sequence and were unique to individuals (Jeffreys et al., 1985, p. 76). He developed a method of identifying “sets of hypervariable minisatellites to produce somatically stable DNA ‘fingerprints’ which are completely specific to an individual (or to his or her identical twin)” (Jeffreys et al., 1985, p. 76). In 1987, DNA analysis was used in a case to bring to justice Colin Pitchfork who confessed to raping and murdering two girls in an English village in the 1980s. Trace DNA from semen samples obtained at the scenes of the crimes was used to make Pitchfork’s DNA profile was matched to the DNA from the crime scene. It was the first time in history DNA analysis was used in a forensics case and its arrival had a spectacular effect, particularly among interdisciplinary studies, as the utility of DNA fingerprinting in criminal justice was evident, as it had allowed for the exoneration of one suspect and let to the conviction of the actual perpetrator.
In the 1990s, DNA analysis began receiving a great deal more of attention, as the application of this type of analysis stretched far and wide. Jeffreys’ original system was re-engineered to be simpler, automated and more effective. DNA fingerprinting became known as DNA profiling, and the process of DNA analysis became a staple of forensics laboratories all over the globe. However, DNA analysis is only one step in the criminal justice process, and as the O. J. Simpson case showed, there are ways around getting DNA evidence accepted in court or regarded by a jury—especially if doubts about chain of custody can be risen. Two cases in particular helped to show the limitations of DNA analysis and its applicability in criminal justice: the case of People vs. Castro in New York in 1989, in which the Court found that DNA analysis was more useful in exclusion than in inclusion, and the case of Amanda Knox in Italy in the 2000s (Roewer, 2013), which similarly examined the limitations of DNA analysis in pinpointing the exact identity of a perpetrator of a crime.
As DNA analysis is still somewhat new to the field of criminal justice, being under four decades old, there is much room for growth, both as a professional tool that can be reliably used in criminal investigation and in terms of social acceptance. DNA analysis has played a large role in high-profile criminal cases that have caught the attention of the public over the decades, and this has not always had positive ramifications for the field of DNA analysis. As in any type of profiling, there is more art to it than science, some DNA analysts view the field as something that should be used in a role that is more supportive of investigative police work and not relied upon as a main source of evidence. DNA analysis is not yet completely exact, nor does it offer exact methods of identification, considering the fact that it still has a relatively small database and not everyone’s DNA is on record. Were everyone to contribute to a DNA database and allow a DNA profile to be constructed, the use of DNA analysis in the gaining of evidence would likely be much more palatable.
How DNA Analysis is Used Today
Today, DNA analysis is a helpful indicator—a clue—that investigators can use to help reconstruct the scene of a crime. While DNA analysis has its uses in some cases, such as where an accused may attempt to prove his or her innocence through DNA evidence (or lack thereof), there are plenty of instances in which DNA evidence can be manipulated or faked or even completely misunderstood (Austin, 2015; Worth, 2018). The limitations of DNA analysis, however, do not prevent its applicability in the criminal investigation process, as a case from 2002 in Europe shows.
In 2002, woman in Berlin was attacked in her apartment building and nearly killed. The medical community was able to save her life and the story she told to investigators about her attack included a single man, who entered her room and attacked her. Blood was found on the glass used to smash the woman’s skull as well as on two towels and a baseball cap. The tenant next door was first suspected as the DNA that was analyzed revealed a DNA pattern that was consistent with his own. However, the tenant had not actually been in town at the time of the attack and had a solid alibi. So suspicion fell to one of the two other men who were staying in his flat at the time. They were related, moreover, and the police used haplotyping to obtain more information about the suspect. Haplotyping in DNA analysis was able to show that the population from which the suspect came was not African but rather South European. The police then located the original tenant and used his help to locate one of the other two men who was staying in the flat at the time. It turned out that the other man was an uncle to a younger man, his nephew, and that because of the relationship he was unable to talk. However, investigators had data from their DNA analysis that led them to believe that the nephew was likely the perpetrator and they used their DNA evidence to help motivate the uncle to come clean about what he knew. In other words, the DNA analysis did not prove anything conclusively, but it was one more clue that investigators could use to help narrow the pool of suspects to a single source and then use that information to help pry more information out another person who was close to the suspect. In the end, the nephew was arrested, and it turned out he had already committed another theft with violent assault (Roewer, 2013). In this example, DNA analysis helped to turn the tide of an investigation.
To make DNA analysis effective, DNA databases are now maintained. However, this has given rise to protests about ethics violations, as DNA databases can include DNA evidence from victims as well as from suspects or criminals. While the more information collected in a database, the more robust it becomes, the problem that civil rights advocates have is that this type of collection violates the privacy of individuals who were never suspected of a crime but were rather victims of one and therefore should not have their personal DNA added into a database used to detect or identify suspects in criminal cases (Roewer, 2013). The argument against this, of course, is that DNA analysis is made better when it has more information to go on, especially when it comes to correlating variables and conducting searches in the database to better understand the DNA profile. DNA analysis does not always have to be used to identify a suspect; sometimes it can be used to distinguish between victims, etc. This is an important point to consider and it is one that the field of DNA analysis is particular sensitive to as it concerns the overall parameters of when DNA analysis is acceptable or permitted and when it should not be.
What is in Store for the Future
The future of DNA analysis depends very much on the manner in which DNA forensic technology is developed in the coming years. DNA sequencing is one aspect of analysis that experts in the field want to see developed more fully. In forensics, DNA sequencing involves a form of DNA testing that focuses on identifying specific genomes in a DNA strand that will allow the analyst to create a wholly unique and individualized pattern to be used for identification purposes. As every human being has a unique DNA pattern, the idea behind DNA sequencing is that this pattern can be determined to help identify suspects in a criminal case. Already, Next Gen sequencing technology is available to aid DNA analysts in DNA sequencing in the field of forensics (Roewer, 2013).
However, Next Gen sequencing technology also produces a high rate of error and so it is not promoted by all in the field. To reduce the rate of error, more development in this direction is required so that in the future DNA analysis can be conducted with more certainty. Other areas of focus exist, though, and these include developing a more rapid response for DNA profiling to assist in criminal cases.
As police work to develop an investigation and build a case, DNA analysis is useful, but time is of the essence. Law enforcement agencies are likely to decide in the near future on what to do about using “commercial instruments capable of producing a database-compatible DNA profile within 2 hours” (Roewer, 2013, p. 24). These instruments are available in the commercial market but law enforcement is still looking into the applicability in the criminal justice field. The application is in its utility, as “the hands-free ‘swab in-profile out’ process consists of automated extraction, amplification, separation, detection, and allele calling without human intervention. In the US the promise of on-site DNA analysis has already altered the way in which DNA could be collected in future” (Roewer, 2013, p. 25). Indeed, the Supreme Court ruled in Maryland v. Alonzo Jay King, Jr. that law enforcement officers may take a swab of an arrestee’s check to obtain DNA information for their databases, similar to the way they take fingerprint information for all arrestees (Roewer, 2013). The purpose here is to build out the DNA database so that better DNA analysis can be conducted by investigators and analysts in the future.
As a result of the Supreme Court’s ruling it is highly likely that DNA analysis will become one more metric by which investigators can determine whether a person should be considered a suspect in a crime. However, in other countries, DNA analysis is limited to exclusion purposes only and not for inclusion purposes, like in Germany (Roewer, 2013). In the future, it would be beneficial to have a global DNA database to facilitate DNA analysis, but because of national laws and perspectives on DNA profiling that are different in various parts of the world (for example, in the U.S. criminal justice law is much more accommodating than in parts of Europe), this vision may take a great while before it is actually brought to fruition.Till then, false matches are likely to continue to occur as more robust DNA databases are required to obtain better verification of match results.
Conclusion
DNA analysis got its start in the 1980s in England when Jeffreys identified a method for linking the human genome sequence of blood samples to individual persons and being able to distinguish between individuals based on their DNA sample. This had tremendous impact on the field of forensics, as it became understood that DNA analysis could help in exonerating and indicting suspects, as happened in the case of Pitchfork in England, following the discovery of Jeffreys’ method. Over the years, that method has been refined and new DNA testing technology has been developed to help in the automated reading of DNA samples. Today, DNA databases are being created to help in the more efficient use of DNA analysis.


References
Austin, E. (2015). DNA evidence can be faked. Retrieved from
https://www.forensicmag.com/news/2015/02/dna-evidence-can-be-faked
Jeffreys, A. J., Wilson, V., & Thein, S. L. (1985). Individual-specific ‘fingerprints’ of
human DNA. Nature, 316(6023), 76-79.
Roewer, L. (2013). DNA fingerprinting in forensics: past, present, future. Investigative
Genetics, 4(1), 22.
Worth, K. (2018). Framed for murder by his own DNA. Retrieved from
https://www.themarshallproject.org/2018/04/19/framed-for-murder-by-his-own-dna