Identification via DNA Profiling in Forensics

The investigation into a recent explosion near Red Fort involves matching the DNA of Dr. Umar Nabi Bhat's mother with unidentified bodies from the site to determine if he was a victim.

Importance of Mother's DNA

• Reliable Identification Tool: DNA testing is crucial for identifying bodies in cases where they are unrecognisable due to severe damage.
• Kinship Analysis: Compares the victim's DNA with biological relatives, using the mother's DNA as a direct and reliable reference.
• Utilization of more preserved body parts like bones or teeth for DNA extraction in extreme conditions.

Methods of DNA Identification

• Autosomal Short Tandem Repeats (STR) Profiling:
  • Involves unique patterns of repeating DNA sequences.
  • 50% match of STR markers with the mother's DNA confirms identity with high accuracy.
• Mitochondrial DNA (mtDNA) Analysis:
  • Used when nuclear DNA is too damaged.
  • Confirms maternal lineage as mtDNA is inherited exclusively from the mother.

STR Profiling Process

• Collection of biological materials like blood, saliva, bone, teeth, or tissue.
• DNA extraction and quality assessment using gel electrophoresis and nano-drop spectrophotometer.
• Polymerase Chain Reaction (PCR) Amplification:
  • Amplifies selected STR regions to make the DNA detectable even in small quantities.
• Separation and analysis of DNA fragments through capillary electrophoresis.
• Generation of DNA profiles using GeneMapper software and comparison with known samples.

Challenges in DNA Profiling

• Degraded DNA due to heat and chemicals.
• Contamination from improper handling or sample mixing.
• Inadequate amounts of DNA available for analysis.
• Mixed DNA profiles when dealing with remains of multiple individuals.