The Effect of Elapsed Time on the Quantity of mRNA in Skin: A Study to Evaluate the Potential Forensic Use of mRNA to Determine the Postmortem Interval

Molecular technology using deoxyribonucleic acid (DNA) is widely used in the field of forensic science. However, ribonucleic acid (RNA) is less widely used because of the rapid decay rate of RNA. Nevertheless, it has been suggested that RNA may have potential applications in the field of forensic science. For example, the fragility of RNA could be exploited to help determine the postmortem interval (PMI) if there is a correlation between the quantity of residual RNA and elapsed time. Bauer et al 3) suggested a method of quantifying messenger RNA (mRNA) as an indicator of PMI. On the other hand, Heinrich et al failed to detect a correlation between PMI and RNA degradation. There is no firmly established method to evaluate the integrity, stability or quantity of RNA in degenerated specimens. Previous studies which tried to show the relationship of RNA and PMI have used percentage of poly A in total RNA, quotient of areas drawn by capillary electrophoresis in two genes, 3) copy numbers or cycle threshold (Ct) value of a certain gene by real-time polymerase chain reaction (PCR), 6-11) or ratio of Ct value in two genes by real-