DNA in the context of "fingerprinting" primarily refers to DNA fingerprinting (also known as DNA profiling or DNA typing), which is a technique used for identifying individuals based on their unique genetic makeup, much like traditional physical fingerprints are used.
As the reference states: DNA fingerprinting, also referred to as DNA profiling and DNA typing refers to the identification of an individual based on his or her DNA profile. This technique examines specific regions within a person's DNA that are known to vary greatly between individuals.
Why Call it a "Fingerprint"?
The term "fingerprint" is used as an analogy because, like traditional physical fingerprints left by the ridges on a person's fingertips, certain patterns in an individual's DNA structure are highly unique. The reference notes: It is referred to as a fingerprint because portions of the DNA structure of certain genes are as unique to each individual as fingerprints. While two people might share most of their DNA, these specific variable regions create a profile that is distinct for almost everyone (except identical twins).
How DNA is Used for Identification
Instead of looking at the swirls and loops of a physical fingertip impression, DNA fingerprinting analyzes specific sequences or lengths of repeated DNA segments at various locations (loci) on chromosomes.
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Biological Samples: DNA for profiling can be obtained from various biological sources left behind at a scene or collected from an individual, such as:
- Blood
- Saliva
- Hair roots
- Skin cells
- Semen
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Creating a Profile: Scientists amplify and analyze these variable DNA regions, often using techniques like Polymerase Chain Reaction (PCR) and gel electrophoresis or capillary electrophoresis. The result is a DNA profile—a pattern of peaks or bands representing the lengths of the DNA fragments at each analyzed locus.
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Comparison: This DNA profile can then be compared to profiles from known individuals or databases to establish connections, identify suspects, or confirm relationships.
Key Uses of DNA Profiling
DNA fingerprinting has become an indispensable tool in various fields:
- Forensic Science: Linking suspects to crime scenes, identifying victims, or excluding innocent individuals.
- Paternity Testing: Determining biological parentage.
- Identification: Identifying human remains, especially in mass disasters.
- Genealogy: Tracing ancestry and family relationships.
In essence, DNA in "fingerprint" (specifically DNA fingerprinting) refers to the unique genetic information contained within a person's DNA that can be used to identify them, paralleling the function of a traditional physical fingerprint.
