Which of the following specimens collected at a crime scene is intrinsically UNSUITABLE as a source of nuclear DNA for STR profiling?
- A Buccal epithelial cells on a drinking glass rim
- B Mature erythrocytes in a dried bloodstain ✓
- C Leukocytes in a fresh bloodstain
- D Hair follicle with attached root sheath
Correct answer: B. Mature erythrocytes in a dried bloodstain
Explanation
Mature circulating erythrocytes extrude their nuclei during maturation and contain no genomic DNA, so a pure red cell fraction cannot be STR typed. Bloodstains still usually profile successfully because leukocytes contribute nucleated DNA. Buccal cells and anagen hair roots are nucleated and are standard sources. This is why blood group testing works on serum or cells but nuclear DNA work depends on the white cell component.
Reference: Krishan Vij, Textbook of Forensic Medicine and Toxicology, 5th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.