Discipline: Biological Sciences
Kati Cranmore - Alabama State University
Co-Author(s): Sheree Finley, Alabama State University, Montgomery, AL; Jack Ballantyne, University of Central Florida, Orlando, FL; Gulnaz Javan, Alabama State University, Montgomery, AL.
Messenger RNA (mRNA) transcript expression patterns of the 25,000 human genes have the potential to elucidate the secrets of how human beings die. There is a cascade of postmortem molecular events that occur involving mRNA transcript abundance and gene expression patterns in internal organs of the decaying human body. Thanatotranscriptomic (postmortem transcriptome) reveal the cellular state of a cadaver at the time of death. Transcriptome analyses of postmortem mRNA from a tissue fragment may determine unique molecular identifiers for specific organs and demonstrate unique patterns of gene expression that can provide essential anatomical information. In cases where the source of the organ tissue is undetermined, advanced molecular methods are required to aid in successful determinations of organ tissue sources made by trained forensic personnel. We hypothesize that certain gene biomarkers determine transcriptional changes caused by the interruption of biological processes. In the current study, we assessed the impact of targeted transcriptome analysis using RNA-seq to reveal changes in postmortem gene expression in hepatic tissues from 27 cadavers from Italy and the United States with times of death ranging from 3.5 hours to 37 days. As a control, commercial liver tissues from a tissue bank were used. Eight liver tissue-specific gene biomarkers (e.g. AMBP and AHSG) were used in this study. The result demonstrated that autopsy-derived organ samples were correctly identified as tissues originating from postmortem livers. According to the findings, 98-100% of sequencing reads were mapped to postmortem liver biomarkers. Our results indicate that gene expression patterns of mRNA exposed up to 37 days of autolysis, can be used to validate the identity of tissue fragments. These results represent the first comprehensive study to evaluate transcriptomic profiles after organismal death in actual criminal casework cadavers up to 37 days. The future question will include the evaluation of mixed tissue organ samples to train and test our tissue identification model to determine other internal organ tissue sources.
Funder Acknowledgement(s): National Institute of Justice 2017-MU-MU-0042 US Department of Education, The Minority Science and Engineering Improvement Program P120A150008 National Science Foundation HBCU-UP HRD 1911660
Faculty Advisor: Dr. Gulnaz Javan, firstname.lastname@example.org
Role: In conducting this research I performed i) RNA extraction from cadaveric liver tissues, ii) RNA quantitation iii) cDNA synthesis.