How is DNA profiling applied in paternity tests and forensic investigations?

Sourav PanNovember 8, 2024

Answered

DNA profiling plays a crucial role in both paternity testing and forensic investigations, leveraging the unique genetic markers present in individuals to establish biological relationships and identify suspects. Here’s how DNA profiling is applied in these two contexts:

DNA Profiling in Paternity Testing

1. Process Overview: Paternity testing typically involves the analysis of specific regions of DNA known as short tandem repeats (STRs). The current standard method utilizes 16 core STR loci, which are compared between the child and the alleged parents to determine biological relationships.
2. Steps Involved:
   • Sample Collection: Biological samples (usually buccal swabs) are collected from the child and both parents. This non-invasive method is suitable for individuals of all ages, including newborns.
   • DNA Extraction: DNA is extracted from the collected samples using established protocols.
   • Amplification: Polymerase chain reaction (PCR) is employed to amplify specific DNA regions, allowing for sufficient quantities to be analyzed.
   • STR Analysis: The amplified DNA is analyzed to identify the alleles at each STR locus. A comparison is made between the profiles of the child and the parents. If the child’s alleles match those of the alleged father at a sufficient number of loci, he can be confirmed as the biological father with a high probability (often over 99.99%).
3. Importance: Paternity testing is vital in legal contexts, such as child support cases or custody disputes, and can also be used to establish familial relationships in genealogical research.

DNA Profiling in Forensic Investigations

1. Application in Crime Scenes: In forensic science, DNA profiling is used to link suspects to crime scenes by comparing DNA found at the scene with that of suspects or victims. This technique has revolutionized criminal investigations by providing a reliable method for identifying individuals based on biological evidence.
2. Steps Involved:
   • Evidence Collection: Biological samples such as blood, saliva, or hair are collected from crime scenes. These samples may contain minute amounts of DNA.
   • DNA Extraction and Analysis: Similar to paternity testing, DNA is extracted and amplified using PCR techniques. Various methods are utilized depending on the quality and quantity of the available DNA, including low copy number (LCN) profiling for degraded samples.
   • Comparison with Suspects: The extracted DNA profile from crime scene evidence is compared against profiles stored in databases or obtained from suspects. This comparison helps identify or exclude potential perpetrators based on matching STR patterns.
3. Role in Legal Proceedings: DNA profiling serves as critical evidence in court cases, helping to establish guilt or innocence. It can exonerate wrongfully convicted individuals and provide strong links between suspects and criminal activities