by Staff Writers
Boulder, Colo. (UPI) Sep 26, 2013
A so-called microbial clock may help determine the time a person dies, research led by the University of Colorado-Boulder indicates.
The clock is essentially the succession of bacterial changes occurring postmortem as bodies go through the decay process, the university said in a release.
Researchers used mice for the latest study, but previous studies on the human microbiome -- the estimated 100 trillion or so microbes that live on a body -- indicate there is reason to believe similar microbial clocks tick away on human corpses, said Jessica Metcalf, a CU-Boulder postdoctoral researcher and lead author of the study.
"While establishing time of death is a crucial piece of information for investigators in cases that involve bodies, existing techniques are not always reliable," Metcalf said. "Our results provide a detailed understanding of the bacterial changes that occur as mouse corpses decompose, and we believe this method has the potential to be a complementary forensic tool for estimating time of death."
Using high-technology gene sequencing techniques on bacteria and microbial eukaryotic organisms such as fungi, nematodes and amoeba postmortem, researchers said they pinpointed the time of mouse death after a 48-day period to within about four days.
The results were more accurate after an analysis at 34 days, correctly estimating the time of death within about three days, Metcalf said.
The researchers tracked microbial changes on the heads, torsos, body cavities and associated grave soil of 40 mice at eight different time points during the 48-day study.
The stages after death include the "fresh" stage before decomposition, the "active decay" that includes bloating and subsequent body cavity rupture, and "advanced decay," said Chaminade University forensic scientist David Carter, a co-author on the study.
"At each time point that we sampled, we saw similar microbiome patterns on the individual mice and similar biochemical changes in the grave soil," said Laura Parfrey, a faculty member at the University of British Columbia. "And although there were dramatic changes in the abundance and distribution of bacteria over the course of the study, we saw a surprising amount of consistency between individual mice microbes between the time points -- something we were hoping for."
Darwin Today At TerraDaily.com
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|