DNA Databases use in forensic science

What are DNA databases

• Powerful tool to solve crimes, identify suspects, and exonerate innocent individuals

• Emerging from the development of DNA profiling in 1980s

• Store genetic profiles

• For identification and comparison

• comparing unknown profiles collected from crime scenes with known profiles from suspects or convicted individuals

• Facilitate 'matches'  linking suspects to crime scenes and identifying victims

Examples of DNA databases

CODIS in the United States, National DNA Database (NDNAD) in the United Kingdom, and international initiatives led by INTERPOL show global impact of these technologies.

Why are DNA databases useful

Identified individuals, enhanced conviction rates, closure to cold cases, and exonerated many individuals who were wrongfully accused.

Issues with DNA databases

Rapid expansion = raised ethical, privacy and legal concerns

Addressed so DNA databases can continue to be responsibly used whilst upholding justice.

Identification of suspects

• Compare genetic material found at crime scenes with profiles from known individuals in the database.

• 'match' or 'hit' found

• Links suspect to crime scene

• Direct matching is effective because many crimes are committed by repeat offenders who are already in the database (McEwen, 1995, Langan and Levin, 2002, Langan et al., 2003)

• Familial searches

• Partial matches between crime scene DNA and close relatives of suspects

• Narrow down suspect not present in database

• Familial searchers are controversial

• Ethical concerns about privacy, informed consent

• Involve individuals who have not contributed DNA

Cold case resolutions

• Further funding allows for review of cold cases

• DNA testing may not have existed at the time of the crime

• Familial searching particularly useful

• For example the 'Grim sleeper' serial killer case

• familial DNA helped catch a killer after 25 years.

• The killer, Lonnie David Franklin Jr., was linked to a series of murders using DNA evidence, despite not having direct matches in databases.

• Reduced stringency searching led to the identification of a close relative in the database

• narrow down the suspect previously not on police radar

• Familial searchers are controversial

• Depend on careful protocols and ethical considerations to protect privacy.

Identification of missing people/victims

• Used for missing person identification and disaster victim identification

• Useful when traditional identification methods - visual recognition/dental records not possible due to condition of remains or nature of injuries

• DNA scientific, reliable solution

• China used its national DNA database to successfully identify and rescue 2455 trafficked children, as of June 2013.

• Disaster victim identification

•  9/11 attacks, DNA analysis was pivotal in identifying victims

• Fragmented and degraded remains

• DNA samples from relatives searched against genetic material from remains

• Separate missing person databases

• National Missing and Unidentified Persons System (NamUs)

• Comparisons between DNA of missing person, samples from other DNA databases -can provide explanations, identify missing person as a victim of a crime

• Humanitarian potential

• Provide closure in complex, unresolved cases

Exonerate the innocent

• Ensure Justice

• Convicting the guilty and exonerating the innocent

• Innocence project

• Overturned over 350 wrongful convictions, mostly based on flawed evidence by using DNA evidence

• DNA can determine presence or absence at a crime scene

• Exclude individuals

• Include others

• Safeguard against miscarriages of justice

• Highlights importance of having accurate and reliable evidence before convicting

• Errors/biases lead to severe consequences

Improve accuracy and reliability of forensic cases

• Enhances accuracy and reliability

• Uses DNA

• scientifically unique except in the case of identical twins

• Probability of two unrelated individuals sharing identical DNA very low

• Reliable indicator of people present at a scene/linking crimes to the same perpetrator

• Less prone to human error and bias than other crime solving techniques; eyewitness testimony - human memory and external influence

• DNA offers scientific, objective methods

• However still challenges in intepreting DNA evidence:

• Dror and Hampikian (2011) highlighted variability in how forensic experts interpret DNA evidence lead to differing conclusions.

• Intermediary DNA transfer - can complicate the reliability of findings

• Challenges in interpretation, ongoing advancements to improve objectivity and integrity of DNA evidence

Improve speed and efficiency of forensic cases

• Advancements in technology

• Automated systems

• Rapid matching of DNA profiles

• large volumes of data, minimal time

• Rapid DNA analysis - profiles generated in hours instead of days

• Allows law enforcement to act quickly

• Critical in time sensitive cases - abductions

• Can be issues with backlogs - can't keep up with volumes of submissions

• Technological improvement, investment

• Reducing processing times very valuable

• can act during active investigations

• Maintaining efficiency important

Deter criminal activity

• Knowledge of DNA evidence -

• highly reliable and catalogued

• Even the smallest trace

• Can link an individual to a crime

• Prosecution

• Powerful deterrent

• Convicts already in the DNA database

• Less likely to reoffend because their DNA profile can immediately connect them to new crimes

• Increasing perceived risk of being caught acts as a preventative measure

Invasion of privacy

• DNA contains highly personal information

• Forensic databases focus on non coding markers unrelated to genetic diseases

• Only useful for identification

• Privacy concerns due to sensitive nature of DNA

• Storing people's information, especially non convicted individuals raises concerns

  • Infringes on the right to presumptive innocence

  • Can lead to stigmatisation of individuals who have not been found guilty of any crime

• Potential for data misuse - unauthorised access, non forensic purposes

• Sharing forensic DNA data across borders (Prum treaty, Interpol initiatives)

• Global collaboration of solving crimes

• Amplifies privacy risks

• The argument for including more people in the database is as the number of profiles increases as does the likelihood of finding a match

• research found that the performance of the DNA database depends more on efficiency and inclusion of the right profiles than the number of profiles.

• This challenges the argument for indiscriminate inclusion, and underscores the need for ethical practices

• It is important to establish legal frameworks to address these challenges to continue to use DNA databases responsibly

Lack of consent

• DNA collected from individuals during criminal investigations - without explicit consent

• Retaining profiles from people later acquitted/found innocent

• Familial searching - DNA indirectly implicated in investigations without knowledge or agreement

• DNA collected from deceased individuals

• DNA collected from secondary sources (discarded items)

• Bypass informed consent

• Ancestry DNA databases - people don't understand or agree to being used in law enforcement

• People don't understand how their DNA is being used

• Legal framework

Representation

• Historical inequalities and discriminatory practices

• Communities more likely to be surveilled, arrested and convicted

• Overrepresentation of minority populations

• Exacerbates systemic biases

• Increases likelihood of implication, adventitious matches

• Mitigate concerns

  • Equitable data collection

  • Legal protections

• Ensure ethical use of DNA databases

Technological developments

Expanding number of loci

• Improves detail

• Improves accuracy and likelihood of matches

• Enhances ability to compare profiles across countries

Massively Parallel Sequencing/Next Generation Sequencing:

• Current profiling techniques (capillary electrophoresis) analyse a relatively small number of genetic markers (20-30 STRs)

• MPS allows for simultaneous analysis of larger number of markers

• Y chromosome: paternal lineage, useful in familial searches, male DNA

• mtDNA: maternally inherited, identifying individuals where nuclear DNA is degraded

• SNPs: variations at single positions in the DNA sequence - information about genetic diversity, ethnicity, ancestry, phenotype

Advantages

• Analyse DNA from a wider range of markers

• Enhance accuracy - higher likelihood of correct matches

• More detailed profiles - store more information, better differentiation

• Improve ability to link to crimes and identification of missing persons

  

Legal framework

• Laws to define DNA collection, individuals whose DNA can be stored, use of the database

• Different countries have varying laws

• Most allow for collection of DNA from convicted offenders

• Some from any arrestees - raises concerns about presumption of innocence

• Voluntary submissions - familial searches, missing person investigations

• Retention periods

  • UK - non convicted individuals deleted after certain time unless linked to ongoing

  • EU - data only kept as long as necessary

  • Automatic deletion of non convicts

• Privacy

  • Non coding regions

  • Access restriction - law enforcement agencies

  • Identification purposes

• Cross-Border Data Sharing

  • Prum Convention

  • INTERPOL initiatives

  • Differences in national laws

  • Amplifies privacy risks

• Essential for DNA databases operating responsibly and ethically.