Which statement correctly describes mitochondrial DNA as used in forensic identification?
- A It is inherited equally from both parents and undergoes routine recombination
- B Each individual carries a unique mtDNA sequence that distinguishes him or her from all maternal relatives
- C It exists in hundreds to thousands of copies per cell, improving recovery from old or degraded samples ✓
- D It is confined to skeletal muscle and is absent from hair shafts and bone
Correct answer: C. It exists in hundreds to thousands of copies per cell, improving recovery from old or degraded samples
Explanation
Each cell contains many mitochondria, each carrying multiple mtDNA genomes, giving a copy number far higher than the two copies of any nuclear locus, which explains its success on aged bone, teeth, and shafts of hair lacking roots. Inheritance is strictly maternal with essentially no recombination, so all maternal line relatives share the haplotype and mtDNA cannot individualise within that line.
Reference: Knight's Forensic Pathology, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.