Phenotyping in Crime Scene Investigations: Benefits and Ethical Considerations

Introduction

An effective justice system must ensure that citizens it serves are treated fairly and equally, and that judgments are rendered without delay. However, the complexity of some crimes means it takes longer for justice to be dispensed. To ensure efficiency, forensic science has rapidly grown and become a key feature of some of the most sophisticated crimes.

As such, in recent years forensic scientists have pushed boundaries and embraced cutting-edge technologies to unravel the complexities of some of the most complex crimes. Among the groundbreaking advances achieved by forensic scientists is phenotyping, also known as DNA phenotyping or molecular photofitting. The innovation has emerged as one of the most potent tools, offering unprecedented insights into an individual’s physical characteristics based primarily on their genetic composition. This technology promises to revolutionize crime-solving by providing invaluable leads in cases where traditional methods have faltered.

The Concept of Phenotyping

The field of phenotyping is deeply rooted in genetics, and the profound understanding of an individual’s physical traits is rooted in their DNA makeup. Hopman (2020) notes that forensic DNA phenotyping is a new technology whose specific aim is to predict the physical characteristics of an unknown suspect for crime scene investigations. By analyzing specific sections of a suspect’s genome, known as single-nucleotide polymorphisms (SNPs), a forensic scientist unlocks a treasure trove of information that enables accurate prediction of an individual’s outward appearance (Hopman, 2020). Research shows that the ability to predict the outward appearance of a suspect from DNA material left at a crime scene is a new development in forensic science that will help speed up investigations (Kayser et al., 2023). As such, phenotyping is the analysis of DNA left at a crime scene to predict the physical appearance of the primary suspect.

Advantages of DNA Phenotyping Technology

One of the greatest benefits of phenotyping technology is its ability to provide invaluable insights when traditional DNA profiling has proven inadequate. Specifically, in cases where DNA from a crime scene is highly degraded, phenotyping is invaluable, as it can provide information on the physical characteristics of the individual involved in the crime. Schneider et al. (2019) note that phenotyping is relevant in criminal cases with no STR (Short Tandem Repeat) match.

This technology has enabled the solving of some complex cases whose trails have gone cold through targeted police investigations. Such information provides new perspectives on case-making and, as a result, increases the likelihood that the cases will be solved. Additionally, the increased accuracy and reliability of DNA phenotyping information mean that the risk of errors in solving crimes is significantly reduced.

Application of Phenotyping in Forensic Investigations

One of the most promising applications of phenotyping technology is predicting eye color. Multiple studies show that a carefully curated combination of SNPs can accurately predict an individual’s eye color (Dabas et al., 2022). As such, this research served as the basis for the development of technology focused on identifying suspects by analyzing their eye color. One such technology was the deployment of the IrisPlex system, which enables the simultaneous prediction of blue and brown eye color phenotypes from DNA materials of people from Europe and the Eurasian region. This pioneering work in phenotyping led to an explosion of advances in the field, solidifying this technology as a new and powerful investigative tool that augments police work.

Similar research has also revealed that genetic material is closely related to an individual’s hair color, skin pigmentation, and facial features. With this information at hand, this technology has allowed investigators to reconstruct an individual’s physical appearance and solve seemingly complex crimes (Kayser et al., 2023). This holistic approach to phenotyping holds immense potential, especially for identifying individuals involved in crime. This technology allows police to narrow the scope of their search and, as a result, increase the likelihood of apprehending the individual responsible. Thus, DNA phenotyping technology provides investors with information about suspects, allowing them to reconstruct their physical appearance, increasing the chances of a successful resolution.

The Adoption of Phenotyping Technology in the US

The US criminal justice system handles millions of crimes each year, and one could imagine it would be open to using such a system. However, DNA phenotyping as a means of helping solve crime has faced significant opposition. This reluctance to adopt a potentially game-changing technology is primarily fuelled by concerns about privacy and suspicion that DNA material could be used for other ulterior motives.

Additionally, the structure of the US criminal justice system means that police departments are under the jurisdiction of states and local authorities. As such, federal authorities have no power to compel states to use such technology, no matter its effectiveness. Therefore, it is often the function of states to develop policy on the tools that police under their jurisdiction utilize. In this regard, Florida and California have taken proactive measures to implement a proactive program aimed at exploring the efficacy and efficiency of DNA phenotyping technology (Dabas et al., 2022). These steps aim to assess the accuracy and reliability of data obtained through DNA phenotyping while also addressing the legal and ethical implications that could arise upon full adoption.

Resistance to the Adoption of Phenotyping Technology

Despite its immense potential, especially in the US, phenotyping technology has sparked significant debate over legal and ethical concerns. The opponents of DNA phenotyping maintain that the prediction of physical characteristics based on DNA could inadvertently perpetuate genetic discrimination or exacerbate already deep racial bias and systemic discrimination (Coquet & Terrado-Ortuño, 2023). They also raise concerns about consent and privacy, which are inherent in the collection of genetic information for law enforcement purposes. In essence, those opposed to the widespread adoption of phenotyping technology in the US criminal justice system do not trust that the government can safely keep their data and may use it for other purposes without an individual’s express consent.

The issues raised by opponents of this technology are complex, but they can be systematically eliminated. One of the surest ways to eliminate these concerns is to adopt a robust legal and regulatory framework before deploying DNA phenotyping for crime scene investigations. When stringent guidelines are put in place, individuals are guided on what they can use the collected DNA materials for.

As such, any use beyond the recommended limits would constitute an infringement of the regulations and incur stiff sanctions for the responsible individual. Additionally, there is an urgent need for ongoing public education and dialogue to foster transparency and a culture of trust, especially as it relates to this technology. This would ensure that its adoption is grounded in ethical principles and social acceptance.

Perhaps one of the greatest actions to eliminate doubt about DNA phenotyping is public acceptance of potential inherent biases in phenotyping techniques. As research has consistently shown, phenotyping technology may be prone to biases stemming from the reference population used to develop prediction models (Coquet & Terrado-Ortuño, 2023). This raises concerns about potential inaccuracies or inequalities in application. As such, continuous research on this issue is necessary to develop a more robust prediction model that can guarantee a high degree of accuracy without being captive to the biases characteristic of most predictive models.

While resistance to this technology has largely prevented its widespread adoption in the US, several countries in Europe have allowed its use in cases where an STR-profile match is unavailable. For example, this technology is explicitly regulated and permitted in the Netherlands and Slovakia. It is also practiced in strict compliance with available laws and regulations in the United Kingdom, Poland, the Czech Republic, Sweden, Hungary, Austria, and Spain (Schneider et al., 2019). Additionally, by 2019, the parliaments of Germany and Switzerland were debating the legalization of phenotyping in crime scene investigation (Schneider et al., 2019). However, because phenotyping data is often expressed as a probability, further evidence of successful crime-solving with this technology is needed to convince a skeptical justice system and the public of the need for its adoption and implementation.

Application Beyond Crime Scene Investigations

DNA phenotyping is a high-potential innovation whose application extends beyond identifying a suspect’s physical traits. In particular, this technology is applicable to the identification of deceased individuals, especially in mass disasters with unidentified remains. As research on the topic has shown, phenotyping can assist in reconstructing facial features and physical appearance, allowing families to identify and reunite with their loved ones (Kayser et al., 2023).

This is a compassionate application that underscores the implications of this technology in providing closure and solace to grieving families. Archaeologists have widely used phenotyping to identify ancient remains and reconstruct the physical appearance of their discoveries. This has allowed the generation of better insights that have helped better understand the human revolution and all its peculiarities.

Conclusion

DNA phenotyping represents a major leap forward in forensic science, offering an innovative tool with the potential to transform investigative processes across the criminal justice system. By harnessing the massive data encoded in DNA, phenotyping can provide investigators with invaluable leads that can help resolve cases shrouded in mystery. However, as with any other groundbreaking technology, its implementation poses ethical and legal constraints. Specifically, the use of DNA in solving crime inherently raises consent and privacy issues.

Additionally, in the US, this technology could be misused to exacerbate systemic discrimination. As such, there is an urgent need to improve the predictive model for phenotype technology to eliminate potential bias before it can be rolled out across the US. Further, ongoing public engagement is required to address any concerns people may have about the technology. For now, states with ongoing plans to adopt DNA phenotyping must strike a delicate balance between the need for technology and ethical and legal concerns.

References

Coquet, M., & Terrado-Ortuño, N. (2023). Forensic DNA phenotyping: Privacy breach, bias reification and the pitfalls of abstract assessments of rights. International Journal of Police Science & Management, 25(3), 262–279.

Dabas, P., Jain, S., Khajuria, H., & Nayak, B. P. (2022). Forensic DNA phenotyping: Inferring phenotypic traits from crime scene DNA. Journal of Forensic and Legal Medicine, 88.

Hopman, R. (2020). Opening up forensic DNA phenotyping: The logics of accuracy, commonality and valuing. New Genetics and Society, 39(4), 424–440.

Kayser, M., Branicki, W., Parson, W., & Phillips, C. (2023). Recent advances in forensic DNA phenotyping of appearance, ancestry, and age. Forensic Science International: Genetics, 65.

Schneider, P. M., Prainsack, B., & Kayser, M. (2019). The use of forensic DNA phenotyping in predicting appearance and biogeographic ancestry. Deutsches Ärzteblatt International.