Forensic scientists use DNA to solve crimes for several compelling reasons:
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Uniqueness of DNA: DNA is highly individual specific; with the exception of identical twins, no two people share the same DNA profile. This uniqueness makes it a powerful tool for identifying suspects or victims in criminal investigations.
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Preservation of Evidence: DNA can be collected from various sources, such as blood, saliva, hair, skin cells, and bodily fluids, which can often survive in a crime scene for extended periods. This allows forensic scientists to analyze evidence long after the crime has occurred.
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Movement and Transfer: DNA can be transferred from one person to another or from an object to a person (e.g., through touch or bodily fluids). This property can help establish connections between suspects, victims, and scenes.
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Database Comparisons: Many countries maintain DNA databases, such as CODIS (Combined DNA Index System) in the United States. Forensic scientists can compare DNA collected at a crime scene against profiles in these databases to identify potential matches with known offenders.
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Exoneration: DNA evidence can also play a vital role in exonerating innocent individuals wrongfully convicted of crimes. By comparing DNA evidence from crime scenes with samples taken from convicted individuals, it is possible to either confirm guilt or establish innocence.
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Linking Crimes Together: When DNA from a crime scene matches DNA from a different crime scene, it can link two or more cases together, suggesting a pattern or that the same perpetrator is involved.
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Reliability and Objectivity: The scientific nature of DNA analysis minimizes subjective bias. Properly conducted DNA testing follows rigorous protocols and is subject to peer review, contributing to its reliability as evidence in court.
Overall, the use of DNA in forensic science enhances the ability to solve crimes accurately and efficiently, making it an indispensable tool in modern criminal investigations.
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