The effect of room temperature exposure on sweat spot-derived DNA samples through analysis of 143-bp mtDNA D-Loop HVS-1 (nt 16268-16410) and 126-bp HVS-2 (nt 34-159)

Context: Identification is an unavoidable process in forensic setting. DNA analysis is one of several scientifically recognized methods to identify somebody. As an alternative to the largely used DNA specimen, the last object frequently used by the perpetrator or victim can be used as well. Clothes or apparels stick to the outer skin; thus the epithelial cells of the skin can be expected to attach to them. One factor that may affect the quality of DNA is the duration of exposure. From the two DNA analysis methods, mitochondrial DNA (mtDNA) has better durability than nuclear DNA due to its relatively larger amount. Hence, mtDNA has some greater chance of success in the amplification process. Aims: From this study, we would like to understand of the effect of the duration of exposure to room temperature on the quality of DNA derived from sweat spots in Indonesia remaining that the data remains unavailable to date. Setting and Design: This is an analytical experimental research with time-series design. Material and Method: Sweat-spotted clothes that had been worn were subsequently exposed to room temperature for 0, 1, 7, 14 and 20 days. Statistical analysis used: nil. Results: Results showed that longer exposure markedly decreased the concentration of DNA from day 1 to 20 at p < 0.005. Conclusions: Longer duration of exposure to room temperature significantly decreased the quality of DNA derived from sweat spots on clothes. Visualization of PCR detection results show positive (+) detection only on day 0 of exposure on both 143-bp mtDNA HVS 1 and 126-bp mtDNA HVS 2.