What’s the biggest challenge in DNA analysis?

DNA Analysis & Human Identification

• Following the Air India Flight AI-171 crash in June 2025 (Ahmedabad), DNA fingerprinting is being used to identify highly decomposed or fragmented human remains.

• DNA samples from victims’ first-degree relatives are being matched using STR analysis.

What is DNA Fingerprinting?

• DNA fingerprinting identifies individuals by analysing unique regions of their DNA.

• 99.9% of human DNA is identical, but the remaining 0.1% contains variations such as Short Tandem Repeats (STRs).

What are Short Tandem Repeats (STRs)?

• STRs are repeating sequences of 2–6 base pairs in DNA.

• Highly variable among individuals — ideal for identity verification.

• STR markers are the most widely used for:

  • Forensic identification

  • Paternity testing

  • Disaster victim identification

Why STRs are Preferred in Forensics

• Highly polymorphic — helps distinguish between individuals.

• PCR amplification compatible

• Can work with degraded or minimal DNA.

• STRs allow high-confidence matches — even in skeletonised or burned remains.

Process of DNA Sample Collection and Matching

1. Sample Types: Tissue, bone, blood, nails, and body fluids.

2. Preservation:

   • Frozen at −20°C

   • Soft tissues in 95% ethanol

3. Extraction:

   • DNA is extracted and amplified using PCR.

   • Specific primers target STR regions.

4. Separation and Analysis:

   • Gel electrophoresis or capillary electrophoresis.

   • Unique DNA profile generated.

5. Comparison:

   • Matched with profiles from relatives or central databases.

Challenges in DNA Fingerprinting

1. Sample Quality Issues

• Environmental degradation

• Contamination

• Mixed or limited DNA samples

• Leads to ambiguous or false results

2. Data Analysis and Interpretation

• Requires advanced software and trained experts.

• Errors can arise in matching and pattern recognition.

3. Ethical and Legal Concerns

• Privacy of genetic data

• Misuse or misinterpretation of sensitive information

• Consent and data storage regulations

Solutions and Recommendations

• Use of automated systems and multiplex PCR

• Strict standard operating procedures (SOPs)

• Regular training of forensic personnel

• Development of custom screening kits for Indian genetic profiles

Key Role of DNA in Disaster Victim Identification

Notable mass fatality events where DNA was crucial:

• 2004 Indian Ocean tsunami

• 2009 Victorian Bushfires (Australia)

• 2014 MH17 crash (Ukraine)

• 9/11 Terrorist attacks (USA)

UPSC Prelims

UPSC Mains Linkages

GS Paper II:

• Governance and technology: Use of biotechnology in disaster response

• Legal and ethical issues: Genetic privacy, consent

GS Paper III:

• Science & Tech: Application of DNA technology in forensic science

• Disaster Management: Identification and rehabilitation

DNA fingerprinting using STRs plays a critical role in forensic science, especially in disaster victim identification. Despite technical and ethical challenges, continuous innovation, robust data interpretation systems, and proper training can ensure accuracy, respect for privacy, and timely justice.