Can DNA Identify a Person?
Yes, DNA can reliably identify a person, except in the case of identical twins who share the same DNA. This identification is possible because each person's nuclear DNA is unique (excluding identical twins). A sufficient match between a DNA profile from a victim's remains and a known sample from that same victim provides strong confirmation of identity.
DNA identification leverages the unique variations in an individual's DNA sequence. While the majority of human DNA is the same across individuals, specific regions exhibit significant variations, forming the basis for DNA profiling. These variations are analyzed to create a unique DNA profile, acting like a genetic fingerprint.
- Crime scene investigation: DNA found at a crime scene can be compared to a suspect's DNA to determine if they were present.
- Missing persons identification: DNA from remains can be compared to DNA from family members to establish a familial link and potentially identify the deceased.
- Paternity testing: DNA from a child and potential father can be compared to determine paternity.
- Mass disaster victim identification: In large-scale disasters, DNA profiling helps identify victims by comparing DNA from remains with DNA from family members or personal effects.
Several methods utilize DNA for identification:
- Nuclear DNA analysis: This focuses on the DNA found in the cell nucleus, providing a highly accurate individual profile.
- Mitochondrial DNA analysis: This analyzes DNA found in mitochondria, often used when nuclear DNA is degraded or limited, typically tracing maternal lineage.
The process typically involves:
- DNA extraction: Isolating DNA from a sample (e.g., blood, saliva, hair).
- DNA amplification: Creating multiple copies of specific DNA regions for analysis.
- DNA profiling: Analyzing specific DNA regions to generate a unique profile.
- DNA comparison: Comparing the generated profile with other profiles to identify matches.
The accuracy of DNA identification is extremely high, making it a powerful tool in forensic science and other fields. While DNA samples may degrade over time, advancements continue to improve the ability to extract and analyze usable DNA from even compromised samples. As noted in a guide for families dealing with victim identification using DNA, "[i]n many (but not all) cases, DNA can be isolated from human remains or other samples." (Identifying Victims Using DNA: A Guide for Families)
Information from family members can also assist in identification when a direct DNA profile of the missing person is unavailable. (CODIS and NDIS Fact Sheet — FBI, DNA).
