A forensic lab receives a degraded skeletal remain from a mass disaster. Standard autosomal STR profiling fails due to low template quality. Which DNA strategy offers the highest probability of obtaining a profile from severely degraded bone?

• A Nuclear DNA CODIS STR profiling using 20-locus kit
• B Mitochondrial DNA HVR1/HVR2 sequencing ✓
• C Y-chromosome STR haplotyping
• D RFLP (Restriction Fragment Length Polymorphism) analysis

Explanation

Mitochondrial DNA (mtDNA) exists in hundreds to thousands of copies per cell compared to two copies of nuclear DNA, making it far more likely to survive in degraded or ancient samples. Sequencing the hypervariable regions HVR1 and HVR2 of the mitochondrial control region allows identification even when nuclear STRs are unrecoverable. CODIS STR (A) and Y-STR (C) both rely on nuclear DNA which degrades faster. RFLP (D) requires high-molecular-weight DNA and is obsolete in modern forensic practice.

Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.