DNA Extraction from Postmortem Blood: A Pilot Study for Advancing Molecular Diagnostics in Forensic Medicine Casework

Abstract

Background: DNA’s role in forensic practice is widely acknowledged for its unparalleled accuracy in identification. While developed countries have established molecular autopsy programs as early as two decades ago, India is yet to initiate such a program. The isolation of DNA serves as the crucial first step in the molecular autopsy protocol. The postmortem blood sample is one of the good sources for DNA extraction which wasn’t considered with rigor by the scientific community so far.Aims and Objectives: The aim of this study was to investigate the specific time period within which DNA canbe effectively extracted from postmortem blood samples. The objective was to identify if there are patterns in the quality and purity of the extracted DNA based on the postmortem interval. Additionally, the study aimed to investigate if the cause of death influenced DNA extractability.Observation and Results: DNA can be extracted from postmortem blood within a timeframe of up to 72 hours after death, given that the deceased body was preserved in cold storage within 12 hours after death. Both the salting out method and the phenol-chloroform method yielded bands of comparable quality, with the phenol-chloroform method showing a slightly higher DNA yield. The average absorbance ratio was 1.4 for the salting out method and 1.6 for the phenol chloroform method, as determined using a Nanodrop.Conclusion: This study concluded that DNA extraction from postmortem blood samples is feasible within 72hours after death. The integrity of the DNA remained intact during this time, but the quality and purity gradually decreased as the postmortem interval increased. The cause of death did not significantly affect DNA extractability.