Forensic DNA Database Management

Abstract

The development of DNA databases at the national and international levels is one of the most efficient ways to detect and prevent crime and is a powerful tool for identifying missing persons and unidentified bodies. A literature review and analysis of national and international legislation and recommendations provided insight into the current state of forensic DNA database management. As legislation in different countries worldwide is different, the amount of DNA data in national databases greatly varies. The tendency is to achieve a balance between a large database with a high possibility of detecting potential perpetrators and a database with a restricted amount of personal data that pays attention to the protection of human rights. Managing the DNA database according to international recommendations and national laws minimizes outstanding privacy and ethical issues. New sets of DNA data and novel matching techniques can produce valuable investigative leads when other inquiries have not given a result. However, special attention must be paid to the use of genetic data from public sources that lack international guidelines and policies for the protection of personal data. The cross-border comparison of data and exchange of information through different available international instruments provides significant leads for law enforcement and judicial authorities, providing great assistance in improving the resolution of cross-border crime.

1. Introduction

The extent of cross-border crime has shown an increasing need to develop efficient forensic intelligence, including collecting, integrating, and analyzing forensic data. The use of forensic intelligence implies moving away from a reactive strategy aimed at solving individual criminal offenses and focusing on a proactive strategy [1] of combining forensic data with a view to detecting criminal offenses and their perpetrators more efficiently, reducing the number of criminal offenses and preventing crime.

In this context, criminal investigations rely heavily on DNA databases for both intelligence and evidentiary purposes. With the development of DNA technology, “forensic genetics has become a significant resource for criminal investigation and evidence-gathering activities for court proceedings in judicial systems around the world [2].” The establishment of a corresponding DNA database, one of the first forensic intelligence databases [3] on national and transnational levels, is one of the most efficient ways to detect and prevent crime.

A DNA database is a collection of DNA profiles generated from various biological samples that are electronically stored and processed. Comparison and matching of DNA profiles from forensic stains of unknowns with DNA profiles from known persons provide possible investigative leads.

Establishing a national DNA database is of major importance for solving and preventing national and international crimes and is a powerful tool for identifying missing persons and unidentified bodies. In this process, it is important to determine its purpose, such as searching for perpetrators of criminal acts and their detection, identifying identities, preventing identity thefts, finding missing persons, etc. The legislation of each individual country regulates how genetic profiles are to be stored in national DNA databases [4, 5].

In general, databases contain reference DNA profiles of suspects, defendants, convicted, and victims and DNA profiles of traces obtained from biological samples (blood, saliva, sperm, bones, soft tissue, etc.) found at the crime scene, whereas in some countries, they also contain DNA profiles of other individuals who might be of interest during a criminal investigation [6]. Storing genetic profiles in DNA databases is of major importance given that such profiles, in accordance with law, remain available for many years. In traditional criminal investigations, DNA evidence can only be used until the suspect of a criminal offense is identified.

The process of creating forensic DNA databases began in the mid-1990s [6]. The first country that started creating a DNA database was the United Kingdom [7, 8]. Based on experience in the genetic profiling of immigrants, this technique could have much wider application in the criminal justice system. The first national criminal or forensic DNA database was established on April 10, 1995, in England and Wales [4].

The DNA Identification Act of 1994 [9] authorized the establishment of the National DNA Index System (NDIS) in the United States of America. The Federal Bureau of Investigation developed the Combined DNA Index System (CODIS), a software system for DNA data management. It exists at the local, state, and national levels and allows forensic laboratories and states to control their data in accordance with legislative frameworks [10].

The European Union Council Resolution of 1997 [11] invited European Union Member States to consider the possibility of establishing DNA databases for the purpose of exchanging DNA analysis results. The Netherlands established a DNA database in 1997, followed by Austria, Germany, and France.

2. International recommendations for establishing the forensic DNA database

“A forensic DNA database can assist investigations of crimes by linking DNA profiles from crime-related biological trace material to each other and to the possible donors (or their relatives) [12]”. The documents, recommendations and best practice guidelines of relevant international institutions (e.g., the European Network of Forensic Science Institutes (ENFSI) [12] and the Organization of Scientific Area Committees (OSAC) [13]) discuss important aspects of establishing and managing the forensic DNA database.

DNA profiles of known individuals (criminal suspects, convicted offenders) and DNA profiles from biological material from crime scenes are almost always present in a forensic DNA database. The selection of DNA profiles should be valuable for maximizing investigative outcomes and reducing investigative costs.

Some countries have specialized DNA databases of missing persons that contain DNA profiles of biological relatives of missing persons and DNA profiles of unidentified human remains.

DNA databases should also have an elimination database. The persons who come into contact with material evidence, investigating officers, DNA laboratory staff, and visitors should provide their biological reference samples to compare their DNA profiles with forensic DNA profiles in criminal proceedings [14].

The rules for searching and matching DNA profiles should be well defined, and the DNA database should meet strict conditions. DNA profiles must be linked to unique identifiers by a reference number. DNA profiles should be of the highest possible quality and include as many genetic loci (markers) as possible. Standards for storing DNA profiles need to be established, such as the minimum number of genetic loci, the maximum number of alleles per locus, and sample quality. Restrictions for matching DNA profiles and their reporting requirements need to be defined.

2.1 Quality management

Quality control and management are crucial for building and maintaining an effective DNA database. It should be applied to the entire process, including the chain of custody, sample collection, DNA analysis, and data-entry processes, to ensure the accuracy of the information. Laboratory accreditation is becoming the accepted benchmark of forensic DNA laboratories, mostly according to the International Standards Organization (ISO) Standard 17025 [15].

The Council of the European Union established the European Standard Set (ESS) of loci in 2001 [16] to enable the comparison of DNA profiles from different countries. The INTERPOL Standard Set of Loci includes the same loci, with the addition of the Amelogenin locus that determines sex. Until late 2009, the ESS contained only seven loci, which was sufficient for occasional exchanges of DNA data between countries. However, when the massive automated exchange of DNA data began, the chance of adventitious matches became significant. Therefore, the ENFSI recommended that the ESS should be expanded by five additional loci. The Council of the European Union adopted this recommendation in 2009 [17].

In the United States of America, 13 loci were required to store the DNA profile of the person in the NDIS (CODIS). In 2015, the CODIS core locus set was extended to 20 loci [18].

2.2 Legislation

Laws and other regulations govern the collection and use of data in a DNA database, the retention time, and the security of information. When establishing a national DNA database, it is important to determine its purpose, the types of DNA profiles that the database will contain, in what manner the data will be used, and who will be responsible for database management. All activities should have a solid foundation in national legislation.

The European Court of Human Rights (ECHR) practice creates an important basis for the legitimacy of DNA databases. The arguments built in the decisions of the ECHR are of great importance for the debate on DNA databases around the world, mainly due to the theoretical-legal consistency of the analysis consolidated in its jurisprudence [19].

2.3 Personal data protection

All information on individuals contained in a DNA database is personal data, and individuals comply, unless a legal exemption applies, with the national legislation governing personal data protection and other global regulations governing data protection, e.g., the European General Data Protection Regulation [20]. The obligation of all persons involved in collecting, processing, and using personal data is to protect private life and other human rights as well as fundamental freedoms.

2.4 Ethical aspects

DNA profiles are a particularly sensitive type of personal data with the potential threat of violating the privacy of individuals. Unlike other personal data, certain segments of DNA data relating to a person can be used for insights into the person’s state of health and for drawing conclusions about the ethnic origin of an individual. Forensic DNA databases even enable information to be obtained not only about individuals whose data are in the database but also about their biological relatives [21]. Therefore, it is necessary to have a strong regulatory framework at the national level.

Different countries have different criteria and regulatory frameworks that define the types of data that may be stored in DNA databases and the retention period. Article 8 of the Convention for the Protection of Human Rights and Fundamental Freedoms generally protects DNA samples and profiles as well. Paragraph 2 states that there should be no interference by a public authority except in cases when this interference is necessary for the interests of national security, public peace, and order and in cases when it prevents disorder or crime.

There are several ethical issues related to forensic DNA databases. These include the collection and storage of DNA samples, the analysis of biological samples, the use of genetic results, access to DNA databases, the retention period of DNA data, and the misuse of genetic research in forensic sciences [22, 23, 24].

Since the late 1990s, the United Nations Educational, Scientific, and Cultural Organization has issued three declarations on ethical aspects of the analysis of genetic material, emphasizing the importance of the creation of ethical guidelines for forensic DNA databases. These declarations leave the ethical governance of forensic DNA databases to the state that manages the database [25].

3. National DNA databases

Many countries have been investing efforts in addressing legislative, technical, personnel, and infrastructural challenges on the way to the creation of DNA databases. The goal is to achieve a balance between the large database containing many DNA profiles, which would enable the discovery of as many perpetrators of crime as possible, and the protection of personal data, ethical principles, and fundamental human rights [6].

DNA databases mostly contain information about the analysis of autosomal short tandem repeats (STRs), which are most commonly used for identifying crimes and humans. The databases include information about individuals (convicted, defendants, suspects, victims, and other individuals of interest), as well as forensic DNA profiles and DNA profiles from crime scene evidence. The retention period of DNA profiles and the obligation to delete DNA data from the database once this period expires are defined in national legislation [6].

The amount of DNA data in databases greatly varies among countries. The number of individuals whose DNA data are contained in databases results from a dynamic process of entry and deletion of DNA data in accordance with the regulatory framework and the size of the population of a given country [3, 4].

One of the largest DNA databases in the world is the NDIS of the United States of America, which contains more than 23 million profiles [26], followed by 8 million profiles in the National DNA Database of the United Kingdom [27]. Among the European Union countries, France leads the way with 4.2 million profiles, and Germany follows with 1.2 million profiles (Table 1).

Country	No. of DNA profiles in database
Austria	384,098
Belarus	336,408
Canada	535,236
Czech Republic	253,085
France	4,247,382
Germany	1,213,331
Hungary	212,196
Israel	491,380
Japan	1,213,928
Netherlands	328,732
New Zealand	237,269
Russia	734,373
Saudi Arabia	909,745
South Africa	1,240,168
Spain	627,163
Sweden	201,900
Switzerland	268,417

Table 1.

Some of the largest DNA databases worldwide according to the INTERPOL Global DNA Profiling Survey Results 2019.

*

Although mentioned in the text above as the largest DNA databases, the USA and the UK did not provide the information for the INTERPOL Global DNA Profiling Survey Results 2019 and therefore were not listed in the table.

4. INTERPOL DNA database

The International Criminal Police Organization (INTERPOL) has been an important support since the very beginning of the international DNA data exchange. Each country can provide their own DNA profiles to INTERPOL’s DNA database, which was created in 2004. It currently contains more than 247,000 profiles from 84 countries worldwide. The country retains ownership of DNA profiles and control of entry, access, and deletion of data in accordance with the provisions of its national legislation.

The new specialized INTERPOL database for identifying missing persons called I-Familia was launched in 2021 [28]. This is a global database for identifying missing persons or unidentified human remains by kinship DNA matching using DNA samples from family members or through direct matching.

5. Novel techniques and databases

Improvements in molecular and genetic analysis technology, especially massively parallel sequencing (MPS) of forensic samples, have generated a large amount of data in the field of STRs, single nucleotide polymorphism (SNP), and mitochondrial DNA (mtDNA) analysis. It is challenging to store the data generated in a short period, particularly in regard to defining the nomenclature of new types of data. Close international cooperation should lead to solutions that are acceptable for future international exchanges of these data.

5.1 Y chromosome

Molecular analysis of the Y chromosome revealed a Y haplotype. The results need to be compared with those from the Y-haplotype database to confirm paternal lineage affiliation. For this purpose, the national Y-chromosome database can be used, or the global Y-haplotype reference database (YHRD) [29], which is the world’s largest global database of Y-chromosome haplotypes. Its main features are online entries with prior quality control of haplotypes and advanced searching and matching possibilities. It has been used as a global Y-chromosome reference database since 2000, when it became publicly available online [30].

5.2 Mitochondrial DNA (mtDNA)

The analysis of sequences of interest and their comparison is the basis of identification through mtDNA. It is used to link the mother’s line of inheritance. The significance of mtDNA evidence is evaluated through information on the frequency of mtDNA based on the number of a specific sequence within the population [31].

To determine the statistical value of this method, comparisons were made with either national or global mtDNA databases. The most relevant global database used in forensics and human identification, according to mtDNA, is the European DNA Profiling Group (EDNAP) Mitochondrial DNA Population Database (EMPOP) [32, 33]. It serves as the global mtDNA reference and population database with the well-established concept for generating mtDNA data, analysis, transfer, and quality control that meets forensic standards [34].

5.3 Missing persons databases

The purpose of missing persons’ DNA databases is to link DNA profiles of an unidentified person and reference material relating to a missing person or samples from a biological relative. In addition to searching for missing persons, it can be used for disaster victim identification (DVI) and identification of human remains found in mass graves. It should contain DNA profiles of unidentified human remains, persons of unknown identity, missing persons’ biological relatives, or personal objects.

There are two strategies for managing missing person DNA databases. The choice depends on national legislation and specialized computer systems used for storing records and processing DNA data. In some states, the DNA data of missing persons are stored together with other data in criminal databases. In other states, separate missing persons and unidentified human remains databases are established. If two separate databases are used, it is recommended that DNA profiles of missing persons and unidentified human remains are compared with DNA profiles from the criminal database on a regular basis. National databases can provide a powerful tool for identifying missing persons, but they are used for approximately 1% of unidentified recovered remains in the United States of America and even less so internationally [35].

The identification of human remains traditionally relies upon an anthropological assessment. Nevertheless, recent multidisciplinary approaches with anthropologists and molecular biologists have made it possible to include a genetic component and specialized databases (YHRD, EMPOP) for investigations with an unidentified decedent [36].

5.4 Indirect matching

The emerging growth of technology reflects DNA databases with the increase in new searching and matching possibilities. Indirect matching utilizes the sharing of DNA between biologically related individuals to link forensic profiles to known samples. Currently available indirect matching techniques include partial matching, familial searching (FS), and forensic genetic genealogy (FGG), also known as investigative genetic genealogy (IGG). Indirect matching compares the forensic DNA profile to that of known individuals potentially biologically related to the perpetrator. Once candidates are indirectly matched, their biological relatedness is further examined through kinship analysis [37]. Indirect matching has been used to solve challenging cold cases. It can produce investigative leads from DNA evidence when other inquiries have not given a result. However, it is necessary to understand that the DNA profile pool within the respective databases limits indirect searching methods [38, 39].

FS has been in use since 2002, and it represents the search of a criminal DNA database. The goal is to identify and statistically rank DNA profiles that are not a full match but that share some genetic characteristics, which can lead to a possible close familial relationship, i.e., full sibling, parent-child, with limited accuracy at more distant levels. The process of FS can be performed automatically using probabilistic familial genotypes and likelihood ratio (LR) information [40].

FGG (also known as IGG) emerged as a novel investigative tool in 2018. The search in genetic genealogy databases for individuals who share DNA with an unknown DNA sample considered genetically related at some level is presented. Genetic genealogy tools and research methods are used to construct family trees to identify potential biological candidates. The relatives identified in genetic genealogy databases are typically distant relatives, i.e., first cousins and beyond [41]. However, finding genetic relatives can accurately link even distant relatives, such as second or third cousins [42]. In recent years, FGG has become a practical tool that can be used to generate investigative leads [43]. However, “there is an urgent need for forensic scientists, bioethicists, law enforcement agencies, genetic genealogists and other interested parties to work together to produce international guidelines and policies [44]” for using FGG responsibly and effectively, ensuring the privacy and security of used personal data.

6. DNA data exchange

International crime, such as domestic crime, threatens society, business, and institutions. Criminals and criminal groups are present in all countries of the world and often operate across borders. Thus, cross-border comparisons of data and exchanges of information are highly important for criminal investigations and combating crime. The information obtained through data comparison provides significant assistance to law enforcement and judicial authorities.

The cross-border exchange of DNA data has great potential for improving the resolution of criminal offenses on an international level. The international dimension of criminal investigations also requires simplified cross-border data exchange, and it is essential to ensure that proper information is exchanged quickly and efficiently according to predefined rules.

To achieve efficient international data exchange, it is vital to establish international standards for ensuring data accuracy and for controlling data quality. Instructions and guidelines related to international data exchange need to be developed in accordance with national legislation. With respect to DNA, e.g., it should be defined which type of DNA profiles are to be exchanged, how matches are to be reported, and which communication channels are to be used. Standards for the exchange of DNA profiles and the minimum eligibility threshold for DNA profile matches should be defined in advance.

In the European Union, laboratories for DNA analyses must perform analyses in compliance with the ISO/IEC 17025 international standard [15]. This provision ensures efficiency for DNA data exchange between countries by recognizing their equal reliability, regardless of the country that creates the data.

There are several methods for the international exchange of DNA data. Countries can make individual requests for verification through international legal assistance, such as INTERPOL and Europol [45], which mediate the exchange of information and data between countries within the scope of their activities. Automated data exchange by providing direct insight into the DNA databases of other countries significantly accelerates the existing procedures. It enables rapid and simple anonymous access to relevant information from another country. Should the exchange generate a match between DNA profiles, further available personal data and other information are exchanged among countries upon request.

The most significant contribution to international automated DNA data exchange has been achieved in the European Union through so-called Prüm Decisions. The signing of a multilateral agreement between Belgium, Germany, Spain, France, Luxembourg, the Netherlands, and Austria in the town of Prüm in 2005 paved the way for the adoption of European Union Council Decisions in 2008 [46, 47]. This legal instrument binds all member states to initiate automated DNA and other data exchange. Twenty-seven European Union Member States, along with the UK, participated in automated DNA data exchange at the end of 2023, while other European countries, such as Norway, Liechtenstein and Switzerland, are in the process of joining automated DNA data exchange.

Other international instruments enable automated DNA data exchange. Thus, the United States of America arranges the exchange of biometric and biographic data and other information with other countries’ law enforcement authorities through the Prevention and Combating Serious Crime (PCSC) Agreements. The Police Cooperation Convention for South East Europe (PCC SEE) is a multilateral treaty that will allow its signatories, once it comes to force, to exchange the data from their DNA databases.

7. Conclusion

Since their first establishment in the mid-1990s, forensic DNA databases have become valuable tools for police and judicial criminal investigations. When developed in accordance with relevant international rules and recommendations, the DNA database represents a powerful means for detecting and investigating offenses and for assisting the criminal justice system. Cross-border and international cooperation uses the full potential for the exchange of DNA data. Along with the rules that must be followed in creating an effective base, special attention must be given to privacy and data protection. Novel methods of genetic analysis provide new database search and matching possibilities. However, regardless of the development of science, each country has established its own legal framework for quality control and database management.