1. What Is Genetic Analysis?
Genetic identification is a technique that uses differences in an individual’s DNA sequence to identify that individual, establish parent-child relationships, and even identify the perpetrator. This technology has been incorporated into forensic science since the 1990s and has played an important role in criminal investigations. Specifically, it reveals differences between individuals by examining specific portions of a gene’s “short tandem repeat” (STR) sequence. This technique can identify with greater than 99.99% accuracy whether a person is the same person or not.
2. The Impact Of Genetic Testing On Forensic Science
Before genetic analysis was introduced into criminal investigations, physical evidence such as fingerprints, eyewitness testimony, and blood types were the most important pieces of evidence. However, these types of evidence had limitations. For example, blood types could match more than one person, and eyewitness testimony was often ambiguous, so misidentification was not uncommon.
The introduction of DNA testing has greatly advanced criminal investigations: DNA is unique to each individual, and by extracting DNA from remains, even if only trace amounts, it is now possible to prove a link between evidence left at a crime scene and a suspect. This has made it much easier to identify the culprit and reduced the risk of false accusations.
3. DNA Analysis Techniques Used in Criminal Investigations
Various techniques are used in forensic DNA analysis. The following is a list of some of the most common techniques.
3.1 Short repeat sequence (STR) analysis
STR analysis is the most commonly used method in genetic analysis: STRs are repeats of short base sequences in specific regions of DNA, the number of repeats of which differs between individuals, making personal identification possible. It can be matched against police databases (e.g., CODIS) to quickly identify suspects.
3.2 Mitochondrial DNA (mtDNA) Analysis
Mitochondrial DNA is passed from mother to child and is therefore used to reveal maternal kinship. It is particularly useful when there are old remains or only trace amounts of DNA remaining that cannot be analyzed by STR analysis.
3.3 Y Chromosome Analysis
Y-chromosome analysis is used to determine paternal kinship and is particularly important in the investigation of sex crimes, especially when the perpetrator is a male, since the Y chromosome is found only in males and is passed down through the paternal line.
4. Specific Criminal Investigation Applications of DNA Testing
Genetic analysis has been used in many areas of criminal investigation, including
4.1 Sexual crimes and genetic analysis
In sex crimes, DNA samples taken from the victim’s clothing or body can be matched with the DNA of a suspect to identify the perpetrator. Particularly in the re-investigation of unsolved cases, the development of DNA databases has led to an increasing number of cases in which previously unidentified perpetrators have been identified.
4.2 Homicide Cases and DNA Analysis
In homicide cases, it is possible to narrow down the suspect by collecting the DNA of the perpetrator from the remains (blood, skin fragments, saliva, etc.) left at the crime scene. Also, if residue is found inside the victim’s body, its DNA can be analyzed to provide clues for identifying the perpetrator.
4.3 Paternity Tests and the Search for Missing Persons
DNA analysis can also be useful in identifying the identity of a body and confirming the kinship of a missing person. Since DNA can be extracted even from hard tissues such as bones and teeth, even if a body is found, it can be compared with the DNA of relatives to identify them.
5. Evolution Of Dna Identification And Future Prospects
DNA identification technology in forensic science is evolving year by year, and analysis using next-generation sequencing (NGS) technology and artificial intelligence (AI) are being studied. In particular, NGS technology is expected to enable more accurate forensic DNA identification because it can analyze more genetic information more quickly than before.
Artificial intelligence is also helping to analyze large amounts of DNA data and identify criminal patterns. This has been shown to have the potential to make a significant contribution to solving unsolved cases and crimes committed by serial offenders.
6. Ethical Issues Related to DNA Analysis
While DNA testing is extremely useful in criminal investigations, there are ethical challenges. Since personal genetic information is extremely private, the use of DNA databases must be carefully managed from the standpoint of privacy protection.
In addition, the risk of misinterpretation of DNA test results and problems related to the handling of evidence have also been pointed out. For example, if DNA samples collected at a crime scene are contaminated, there is a risk of erroneous test results.
Conclusion
Genetic analysis technology has dramatically transformed criminal investigations in forensic science and has contributed to the resolution of numerous cases. Further development is expected as the technology continues to evolve. On the other hand, however, it also poses ethical issues, and it is important to work on future legislation and privacy protection. It is imperative that forensic specialists and criminal investigative agencies utilize the latest knowledge and technology, while at the same time being aware of their social responsibility and balance in dealing with these issues.
References
- Butler, J. M. (2005). Forensic DNA Typing: Biology, Technology, and Genetics of STR Markers. Academic Press.
- Budowle, B., Schmedes, S. E., & Wendt, F. R. (2017). Next Generation Sequencing and Its Applications in Forensic Science. Frontiers in Genetics.
- National Institute of Justice. (2020). DNA Evidence: Basics of Analyzing.
These references are very helpful for a better understanding of DNA identification techniques in forensic science and the latest developments in their application to criminal investigations!
