DNA fingerprinting is one of the most important applications of molecular biology in forensic science. It helps identify individuals by examining variations in deoxyribonucleic acid (DNA), the molecule that carries genetic information. Most individuals have distinguishable DNA profiles, although identical twins generally share nearly the same inherited genetic profile. Forensic DNA profiling commonly examines specific regions called short tandem repeats (STRs). These regions contain short DNA sequences repeated a variable number of times. Because repeat patterns differ among individuals, they can be used to generate a genetic profile for comparison with reference samples. Suitable biological evidence may include blood, saliva, skin cells, and hair containing usable genetic material. The analytical process begins with the collection, documentation, and preservation of biological evidence. DNA is then extracted from the sample, and its quantity and quality are assessed. Polymerase chain reaction (PCR) is used to amplify selected genetic regions. The amplified fragments are analyzed to determine the STR profile, which can subsequently be compared with profiles obtained from reference samples. Statistical methods help evaluate the strength of the observed correspondence. DNA fingerprinting contributes to criminal investigations, identification of unknown human remains, kinship investigations, and the reassessment of unsolved cases when preserved biological evidence is available. Its value lies in the ability to examine biological material that may not be visible to the naked eye. However, a DNA match does not automatically prove that a person committed a crime. DNA may have been transferred directly or indirectly, and its presence must be interpreted in the context of the circumstances. Furthermore, samples may contain genetic material from several individuals, making interpretation more complex. Reliable forensic DNA analysis requires careful sample handling, contamination prevention, appropriate laboratory controls, and complete documentation. Analysts must consider the quantity and quality of DNA, the possibility of mixed profiles, and the statistical significance of their findings. Overall, DNA fingerprinting is a powerful scientific tool, but its conclusions should be evaluated alongside other forensic evidence and investigative information. المصدر العلمي / Scientific reference: NIST — DNA and Biological Evidence. NIST +1