Typing of deoxyribonucleic acid (DNA) for use in criminal investigations is regarded as an extension of forensic science that has been common in the justice system for over three decades now. It is worth noting that forensic science, including DNA typing, is critical for the administration of justice. At its core, DNA typing involves the genetic determination of variations in genetic content that is critical for the identification of persons involved in crimes (Ferrero, 2017). DNA forensic is a powerful adjunct to the field of forensic science. Since its first use in casework in 1985, in the U.K., DNA forensic has proved to be beneficial in the criminal justice system. However, due to possibilities ranging from abuse, misuse, it is worth investigating the validity of DNA used for forensic purposes. This research paper is a summary, critique, synthesis, and analysis of previous studies regarding the validity of DNA for forensic purposes.
An Overview of DNA Forensic
To comprehend the field of forensic, it is critical to understand forensic science. (Koehler, 2018) reveals that the discipline of forensic science is inclusive of methodologies that range from the analysis of DNA samples to chemical recognition for pattern recognition. The development of forensic practices is enforced and vetted by the legal system based on scientific scrutiny, empirical testing, and application in cases. Opponents of DNA forensics have come up with exonerations that question their validity for use. (Chin, 2018) indicates that the validity of DNA forensic cannot be challenged by its imprudent use or mere claims regarding the accuracy values some of which are beyond plausibility. Based on the findings, scholars urge that the limitations of DNA forensic be evaluated depending on the different cases other than generalization. This will ensure that it remains valid because the obtained profile will be established and deemed suitable for its intended purpose. It is worth noting that just like other methods applied in criminal investigations, DNA has its share of problems. These problems should not dismiss its validity. Furthermore, countries such as the United States have put in place measures and comprehensive programs to provide solutions to both judicial and technical problems that may threaten the validity of DNA forensic.
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Advanced Technologies and Methods
From a technological and methodological standpoint, studies reveal that DNA forensic is valid for use in criminal investigations. A study conducted by (Bell, Sah, Albright, Gates, Denton & Casadevall, 2018) indicates that prior to the developments in DNA forensic there lacked the appropriate experimental approaches that would make it possible to use genetic information in crime scenes investigations. In the early 70s, the basis for analyzing the DNA of individuals was not so advanced because some parts of it relied on the judgement. Scientists understood that cells of human beings contain an equal number of chromosomes that could match with another cell from the same person. The task was daunting especially where the DNS samples involve hair and blood from a person. Similarities outnumber the differences in human beings and the vast percentage of DNA is common to species. Based on the methodologies used back then, the validity of DNA forensic could have been doubted. However with the recent developments made in the field, DNA forensic has become valid in criminal investigations.
Over the last four decades, there have been developments in molecular genetics that have made DNA forensic valid and reliable. One of these developments is the discovery of the DNA region. According to (Haned, Gill, Lohmueller, Inman, K, & Rudin, 2016) geneticists in America discovered a region of the DNA that contains genetic information unique to every individual. The molecule does not hold any genetic information and since then similarities have been found and linked to individuals that could have possibly been linked with crimes. The molecules contain short sequences repeated many times hence the diversity among individuals. Except in the cases of identical twins, the DNA of a person is reliable for practical purposes of a criminal investigation. Further indicating the reliability and validity of DNA forensic.
According to (Hampikian, 2019) there is no scientific dispute regarding the validity of the general principles underlying DNA forensic. The principles provide that DNA has significant and substantial variance among human beings, the variation can be detected under laboratory experiments, and comparison of different DNA samples provides a basis for distinguishing samples among different individuals (Hampikian, 2019). The only variance in methods is the acceptability of a particular method for forensic use in a case.
Usually, there are three universal steps that DNA material must undergo for it to be relied on in forensics. Regardless of the varying methods used in DNA typing each is required to undergo the following steps; “Laboratory analysis of samples to determine their genetic-marker types at multiple sites of potential variation, and comparison of the genetic-marker types of the samples to determine whether the types match and thus whether the samples could have come from the same source” (Hampikian, 2019). In the third step, If the types match, statistical analysis of the population frequency of the types to determine the probability that such a match might have been observed by chance in a comparison of samples from different persons (Hampikian, 2019). Before any testing method is used, procedures that are scientifically reliable for performing the three universal steps must be established. Cases that have used DNA forensic have complied with the three steps over the years. Therefore it is possible to develop valid DNA forensic that can be relied on by the criminal justice system not just in the U.S. but across the world.
Besides the steps, the means of analysis have also proved to credit DNA with validity for forensic use. Approximately two decades ago, most of the forensic laboratories applied the Restriction, Fragment Length Polymorphism (RFLP) analysis. RFLP involves the sequence arrangement of sequences adjacent to each other such that they form blocs. The sequences undergo tandem repetition and are variant in the number of times it is repeated other than what they are composed of. The variable number of tandem repeats does not contain any genetic information. The procedures used back then in DNA forensic were complex. Furthermore, the RFLP involved eight different stages that would require different kits, materials, and procedures. In contrast, the recent advancements in technology revolve around Forensic DNA phenotyping, the use of ancestry informative markers, and familial searching. At its core, Forensic DNA phenotyping refers to a set of techniques that infers visible features of the human being such as hair, eye, and skin color (Machado & Silver, 2019). In addition, FDP involves the analysis of the biogeographical ancestry of criminal suspects based on samples collected at the scene of the crime. The advanced means of analysis are less procedural hence their numerous applications in various jurisdictions. It is worth noting FDP has been applied in high profile cases making them not only reliable but also valid for forensic use. On the other hand, the technique of familial search makes use of the genetic closeness or relatedness of DNA databases through connection with their biological relatives whose profile is in the database system or have been charged with criminal offenses (Machado, 2019). The technological advancements that have taken place in the DNA forensic over the years prove their validity for use in crime investigation.
Kits and Tools used in DNA Forensic
In a recent study involving LCN typing, findings indicate the validity of DNA forensic (Budowle, Eisenberg, & Daal, 2018). LCN typing by its nature cannot be considered robust. However, it has a place in the forensic science toolbox because it enhances the validity of DNA tests. Budowle, Eisenberg, and Daal (2018) define low copy numbers, LCN as the analysis for any sample that has less than 200g of DNA sample. Often LCN is used for the short tandem repeat. In their study, Budowle, Eisenberg, and Daal acknowledge that extensive validation studies have been conducted on DNA forensic kits, the conditions under which they work and the various cases for which they are used to ensure that they produce reliable results (2018). For instance, in 1998, Omagh in Northern Ireland was bombed resulting in the death of 29 people and wounding of 200 others. The application of LCN led to the arrest of Sean Hoey who was linked to the terrorist bombing due to the DNA evidence derived from the use of the kit. Due to the use of LCN, the judge was critical in handling the case claiming that the forensic laboratory was not appropriate enough in the precautions of using LCN typing ((Budowle, Eisenberg, & Daal). From this study, it is worth noting that courtrooms are not the best place for determining the validity of DNA forensic and experts should be cautious of taking criticisms in that arena. Furthermore, the LCN typing used in the United Kingdom is not only robust but also fit for the intended purpose. LCN needs a few recommendations which when followed can be termed valid for use in criminal investigations involving DNA forensic.
Statistical Analysis of Populations
It appears that reliability and validity may be occurring in the reliable ascertaining population of DNA forensic. (Machado & Silva, 2019) reveal that before modern developments, forensic scientists calculated the probability of a person having a particular DNA profile by chance through referring accumulated population frequencies of VNTR that comprise that particular DNA. A large population is required in order to establish the accuracy of the DNA results and make them suitable for use in forensic. Currently, however, there are universal standards that have to be met to get accurate results. The standard way to get accurate and reliable results is by counting the occurrences in the random population and then applying statistical formulas to place both upper and lower confidence limits. For instance, if a particular DNA pattern occurred in one of saying the 100 samples tested, the upper frequency would be 1%. Traditionally the upper bound limit is equivalent to 95% implying that the true value has a limited chance of up to 5% of exceeding the upper limit. Such a modern statistical basis for the interpretation of DNA samples is not dependent on mere theoretical assumptions but actual population. Therefore the improved population and data analysis used in DNA typing make it valid for forensic use.
DNA Database Banks
One of the prominent aspects of forensic DNA validity is not only the establishment but also the expansion of national criminal databases. Usually, these databases are centralized. They contain collected and stored DNA profiles from a range of people who include convicted offenders, volunteers, criminals, and other persons that are of interest to criminal investigations in the justice system. At its core, the DNA database is intended to produce matches between the profile and crime scenes (Machado & Silva, 2019). Across the U.S. all states operate the DNA databases. Therefore the validity of DNA forensic is guaranteed because there are higher chances of having a match from the stored data banks. According to a recent study, there has been an increased population in the DNA database banks. This reveals that the chances of having a match from the profiles can either be low or high depending on the case in question. Therefore, the study arrives at the conclusion that DNA database banks make it DNA valid for forensic use.
In numerous respects, the storing of DNA profiles in database banks is analogous to the latent fingerprints that were originally used prior to the development of DNA forensic. It is worth noting that technology has propelled the development of an Automated Fingerprint Identification System that has enabled the entering or even unidentified fingerprints into the system and comparing them with millions of others in the database for use in crime-scene investigations (Raychlak, 2015). The kind of technology required for the fingerprint identification is termed as sophisticated. Furthermore, fingerprints are characterized by geometric patterns in which the specific computers must recognize search for identification with millions of others in the system. With the DNA databanks, however, the technology required is simple and not prone to errors such as one of the fingerprints (Haned, Gill, Lohmueller, Inman, and Rudin, 2016). DNA profiles can be reduced to genetic types and therefore it is possible for repositories to apply simple software. Consequentially, the simplicity of the software used in DNA typing does not make the results prone to errors. In contrast, they are reliable and sequentially considered to be valid for use in criminal investigation scenes.
Confidentiality and security of the DNA databanks are particularly important because neither the technological revolution of molecular biology nor computer technology networks of sharing information has shown signs of abating. Just like fingerprints can be misused, so can the DNA profile information available in the databases be abused and misused too. In a recent investigation in South Korea, findings reveal that a majority of the citizens were in support of the use of DNA database banks for the purpose of crime investigation (Toom et al, 2016). However, controversies arose when it came to the issue of confidentiality. People’s perception of the validity of database samples differed due to security issues associated with the DNA profiles. The storage of DNA profiles in computers increases the chances of misuse and abuse. Individual information such as telephones, credit ratings, income, and residential addresses are at risk of being shared with other companies without the consent of the owner. DNA profile databases are no different. There is a possibility of information being disclosed which may compromise the validity and reliability in criminal investigations. The United States has put in place strict measures and policies that ensure the DNA databanks are secured and not interfered with so that their validity in criminal investigations among other uses is not compromised.
In conclusion, the use of DNA in forensic is critical in criminal investigations in the modern world. However, there have been controversies surrounding the use particularly in regards to validity. DNA evidence alone might not be enough to secure a conviction in the courtroom today. Despite being dogged by issues such as processing delays, the review, and analysis of literate reveals that DNA in forensic has come a long way in terms of faster progression and increased sensitivity. Therefore, its validity has been proved over the course of these progressions. Furthermore, as revealed by the findings there is no scientific evidence that can undermine the underlying principles under which DNA is used for forensic. In addition, the validity of a method that has been used in some of the most high profile cases in the world cannot be challenged by mere claims of accuracy, abuse, and misuse that are beyond plausibility.
References
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