Effect of room temperature and length of exposure to recover quality DNA from earphone swab-derived 126bp and 143bp mitochondrial DNA at D-loop region

Introduction: Exploration of crime scene devices left over and its surrounding is of significance in forensic identification. The significance is due to its association and/or potential harbor of biological evidence; ie., blood, blood spots, semen patches, vaginal swabs, buccal swabs, bones, or trace evidence. Such harboring of evidence from humankind proposes traceability under Locard’s principle of contact. Materials and Methods: Processing of cerumen expelled or traces logged from the 30 used earphones were subjected to 0, 1, 7, 14 and 20 days room temperature exposure. Results: Length of exposure has a significant effect on decreasing the level of DNA steadily. Visualization of the results of PCR on 143bp (HVS I, nt 16268-16410) mtDNA D-loop region showed a positive (+) detection only for day 1 (4 [66.67%] samples) and day 7 (3[50%] samples). Visualization of the results of PCR on the 126bp (HVS II, nt 34-159) mtDNA D-loop region showed a positive (+) detection only for day 1 (2 [33.37%] of samples) and day 7 (6 [100%] of samples). Conclusion: In conclusion, the length of exposure to room temperature has an effect on the quality of earphone swab-derived DNA. Decreased levels of earphone swab-derived DNA showed a significance value (p<0.005) with regard to the effect of room temperature exposure.