What is DNA Fingerprinting?

March 26, 2025

DNA fingerprinting has revolutionised the fields of forensics, genealogy, and medicine. It is a powerful tool used to identify individuals based on their unique genetic makeup. This technology relies on the analysis of DNA, which is present in every cell of the body.

What Is DNA?

DNA, or deoxyribonucleic acid, is the hereditary material in humans. Each cell contains 46 DNA molecules, arranged in 23 pairs. One set of 23 comes from the mother and the other from the father. This genetic information is stored in chromosomes. Each chromosome carries specific genetic instructions that determine individual traits.

The Role of Polymorphisms

Polymorphisms are variations in the DNA sequence that help distinguish one individual from another. These variations occur within chromosomes and are crucial for tracing ancestry. By analysing these polymorphisms, scientists can identify relationships between individuals and their family trees.

About Short Tandem Repeats (STRs)

Short Tandem Repeats are specific sequences of DNA that are repeated multiple times. These sequences are often polymorphic, meaning that unrelated individuals will likely have different repeat counts. STRs are key components in DNA profiling as they provide unique genetic markers.

Polymerase Chain Reaction (PCR)

PCR is a laboratory technique used to amplify specific segments of DNA. This process involves heating the DNA to separate its strands, adding primers to bind to target sequences, and using DNA polymerase to create new strands. PCR can produce millions of copies from a small DNA sample in a short time.

Capillary Electrophoresis

After amplification, DNA fragments are separated using capillary electrophoresis. This method utilises an electric field to differentiate DNA fragments based on size. Smaller fragments move faster through the capillary, allowing for precise measurement of STRs.

What Is a DNA Fingerprint?

A DNA fingerprint is a unique profile created from an individual’s STR data. This profile is exclusive to each person, making it a reliable method for identification. DNA fingerprints can be derived from various biological samples, including blood, saliva, and hair.

Applications of DNA Fingerprinting

DNA fingerprinting has numerous applications. In forensics, it helps identify suspects and victims in criminal cases. In paternity testing, it establishes biological relationships. In medicine, it assists in organ matching and can even help solve cold cases by re-examining old evidence.

Stability and Longevity of DNA

DNA is remarkably stable. It has been extracted from ancient remains, demonstrating its durability over thousands of years. This stability allows for the re-analysis of evidence in unsolved cases, which has led to the exoneration of wrongfully convicted individuals.

« Previous Post Next Post »