DNA Fingerprinting: Role in Law, Medicine, and National Security

Context:

DNA fingerprinting is a key tool in forensic science, criminal investigations, ancestry tracing, and medical research. It identifies individuals using DNA polymorphisms, aiding justice, security, and genetic studies.

What is DNA?

• Deoxyribonucleic Acid (DNA) is the genetic material in skin, blood, bone, and teeth.

• Humans have 46 chromosomes (23 from each parent).

• Chromosomes contain genes that determine traits like eye color and disease susceptibility.

DNA Polymorphisms & Identification

• Variations in DNA sequences that distinguish individuals.

• Used for crime-solving, paternity testing, and ancestry tracing.

• Forms the basis of DNA fingerprinting.

Short Tandem Repeats (STRs)

• Repeated DNA sequences (e.g., GATC-GATC-GATC).

• Unique to individuals, making them useful for:

  • Forensic identification.

  • Parent-child testing.

  • Genetic studies.

Polymerase Chain Reaction (PCR)

• Amplifies DNA for analysis.

• Key steps:

  1. DNA Extraction from blood, bones, saliva, etc.

  2. Denaturation (95°C) – DNA strands separate.

  3. Annealing (60°C) – Primers bind.

  4. Extension (72°C) – DNA polymerase creates new strands.

  5. Repetition – Multiplies DNA.

What is a DNA Fingerprint?

• Unique genetic profile based on STR variations.

• Created using Capillary Electrophoresis.

• Sources: Teeth, bones, blood, saliva, semen, skin cells.

Relevance to UPSC & Governance

• Forensic Science & Justice: Solves crimes, prevents wrongful convictions.

• National Security: Identifies terrorists, missing persons.

• Medical Research: Helps in disease studies, organ transplants.

• Ethical Issues: Privacy concerns over DNA databases.