Discipline: Biological Sciences
Sheree J. Finley - Alabama State University
Co-Author(s): Gulnaz T. Javan, Alabama State University, Montgomery, AL
Determining the cause of death is crucial in all types of death inquiries, in particular, deaths that involve homicide, suicide, and overdose. The role of the thanatomicrobiome (microbiome of death) in the diagnosis of the causes of mortality has not been fully elucidated. New sequencing and bioinformatics insights have demonstrated that the thanatomicrobiome has the potential to solve many unanswered questions in forensic microbiology. Traditional methods for determining cause of death are concurrence methods (e.g., vitreous humour) and forensic autopsy. We hypothesized that when a human host dies, time-dependent succession of microbial signatures within internal organs are more predictive of the cause of death than current techniques. In this study we demonstrated that the relationship between postmortem microbial community’s succession is measurable and viable in a human thanatos system. Our thanatos model assessed liver and spleen samples from 66 human remains from actual criminal casework with postmortem intervals ranging from 3-78 hours. The cadaver samples were collected by dissected tissues from liver, and spleen of the cadavers. We extracted DNA and amplified microbial DNA using the V4 region of the 16S rRNA gene. The results showed that in a comparison of male and female corpses’ thanatomicrobiomes as well as the liver and spleen samples, there are significant differences (p <0.05) among causes of enforced death (homicide, suicide, and overdose) in both unweighted and weighted Unifrac ADONIS tests. These unprecedented results demonstrate an innovative way to incorporate molecular pathology in ascertaining the cause of and the microbial processes involved in enforced deaths. Future experiments using our thanatos model systems that include a larger cohort of samples from both enforced and pathological deaths and more internal organs will be necessary to determine the potential impact of the relationship between postmortem microbial succession and cause of death. Our results will support the creation of the Human Postmortem Microbiome Project (HPMP), a consortium of endeavors to cultivate forensic and criminal investigative tools and databases for the law enforcement and forensic research communities.
Funder Acknowledgement(s): National Science Foundation HRD 1401075 and 1432991
Faculty Advisor: Gulnaz T. Javan, firstname.lastname@example.org
Role: The part of the research that I did included the traditional phenol/chloroform DNA extraction, polymerase chain reaction and agarose gel electrophoresis to isolate and amplify specific postmortem microbial DNA from internal organs (liver and spleen) from cadavers.