Forensic DNA analysis is based on the principles of genetics and molecular biology (Daeid et al., 2021). Deoxyribonucleic acid (DNA), is the genetic material that contains the instructions needed for successful forensic DNA analysis because of its uniqueness from one individual to another, except for identical twins (Fernando and Nilanga, 2019). The analysis of DNA samples obtained from biological evidences, such as blood, saliva, semen, and hair, provides valuable information for forensic investigations (Arenas et al., 2017).
DNA analysis process road map involves several steps: Collection of biological samples from crime scene, DNA extraction, quantitation, amplification, separation and detection, interpretation and comparison, and finally reporting (Bukyya et al., 2021). Sample collection involves using appropriate techniques to collect materials from the scene to prevent DNA degradation (Bukyya et al., 2021). After that, DNA extraction/isolation of the samples is done using appropriate DNA extraction kits (Gupta, 2019). The targeted DNA sequence repeats such as the short tandem repeats (STRs) e.g. the 13 core CODIS STR loci, single nucleotide polymorphisms (SNPs) or Y-chromosome markers are then amplified using polymerase chain reaction (PCR) technique. There are several techniques used in forensic DNA analysis after PCR, namely; capillary electrophoresis (CE), and next-generation sequencing (NGS) (Tillmar et al., 2018). A DNA profile is created, and analysis is done by discrimination and comparison of multiple STR loci of suspects and the victim (Panneerchelvam, and Norazmi, 2003; Butler, 2023). Population data based on racial or ethnic group are used to discriminate the match between suspects and victim to establish validity of the results (Jobling, 2022). The results are taken to court as proof against the culprit or used to exonerate the innocent (Kaye, 1994).
Forensic DNA analysis has a wide range of applications in the criminal justice system (Schneider et al., 2019). One of the most significant applications of forensic DNA analysis is in the investigation of sexual assaults. DNA evidence can provide conclusive evidence of innocence, even years after the crime was committed (Schneider et al., 2019). Since the introduction of DNA profiling in the 1980s, more than 375 people have been exonerated in the United States alone (Laporte, 2017).
The principles and techniques of forensic DNA analysis are constantly evolving, with new methods being developed and improved upon. Current research in forensic DNA and genetic analysis have focused on the reconstruction of the physical appearance of individuals—DNA phenotyping (Amankwaa and McCartney, 2021).
Conclusively, forensic DNA analysis is a powerful tool that has revolutionized the criminal justice system. As the technology advances, it is likely that forensic DNA analysis will become even more precise and accurate, with the potential to solve even more crimes and exonerate more innocent individuals. It is important to note that proper protocols and quality control measures must be in place to ensure the accuracy and reliability of DNA analysis results. Consideration of ethical and privacy implications of DNA analysis is also essential to reveal sensitive information about an individual’s genetic makeup.
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About the Author
UNIVERSITY OF LAGOS
Faculty Of Science
Department of Cell Biology and Genetics
Postgraduate (Pg.D.) Oral Seminar (CBG701)
Name: AWE, David Oluwadamilare
Topic: Human Forensic DNA Analysis Process Map
Supervisor: Dr. Adebesin O. A.
DATE: 3rd May, 2023.