Science News
from research organizations

'Microbial clock' may help determine time of death

Date:
September 24, 2013
Source:
University of Colorado at Boulder
Summary:
An intriguing study may provide a powerful new tool in the quiver of forensic scientists attempting to determine the time of death in cases involving human corpses: A microbial clock.
Share:
       
FULL STORY

“While establishing time of death is a crucial piece of information for investigators in cases that involve bodies, existing techniques are not always reliable,” said Metcalf of CU-Boulder’s BioFrontiers Institute. “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.”
Credit: © Kelpfish / Fotolia

The research team is working closely with assistant professors Sibyl Bucheli and Aaron Linne of Sam Houston State University in Huntsville, Texas, home of the Southeast Texas Applied Forensic Science Facility, an outdoor human decomposition facility known popularly as a "body farm." The researchers are testing bacterial signatures of human cadavers over time to learn more about the process of human decomposition and how it is influenced by weather, seasons, animal scavenging and insect infestations.

The new study is one of more than a dozen papers authored or co-authored by CU-Boulder researchers published in the past several years on human microbiomes. One of the studies, led by Professor Noah Fierer, a co-author on the new study, brought to light another potential forensic tool -- microbial signatures left on computer keys and computer mice, an idea enthralling enough it was featured on a "CSI: Crime Scene Investigation" television episode.

"This study establishes that a body's collection of microbial genomes provides a store of information about its history," said Knight, also an associate professor of chemistry and biochemistry and a Howard Hughes Medical Institute Early Career Scientist. "Future studies will let us understand how much of this information, both about events before death -- like diet, lifestyle and travel -- and after death can be recovered."

In addition to Metcalf, Fierer, Knight, Carter and Parfrey, other study authors included Antonio Gonzalez, Gail Ackerman, Greg Humphrey, Mathew Gebert, Will Van Treuren, Donna Berg Lyons and Kyle Keepers from CU-Boulder, former BioFrontiers doctoral student Dan Knights from the University of Minnesota, and Yan Go and James Bullard from Pacific Biosciences in Menlo Park, Calif. Keepers participated in the study as an undergraduate while Gonzalez, now a postdoctoral researcher, was a graduate student during the study.

"There is no single forensic tool that is useful in all scenarios, as all have some degree of uncertainty," said Metcalf. "But given our results and our experience with microbiomes, there is reason to believe we can get past some of this uncertainty and look toward this technique as a complementary method to better estimate time of death in humans."


Story Source:

The above post is reprinted from materials provided by University of Colorado at Boulder. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jessica L. Metcalf, Laura Wegener Parfrey, Antonio Gonzalez, Christian L. Lauber, Danknights, Gail Ackermann, Greg C. Humphrey, Matthew J.gebert, Will Van Treuren, Donna Berg-lyons, Kyle Keepers, Yan Guo, James Bullard, Noah Fierer, David O. Carter, Rob Knight. A microbial clock provides an accurate estimate of the postmortem interval in a mouse model system. eLife, September 2013 DOI: 10.7554/eLife.01104

Cite This Page:

University of Colorado at Boulder. "'Microbial clock' may help determine time of death." ScienceDaily. ScienceDaily, 24 September 2013. <www.sciencedaily.com/releases/2013/09/130924153953.htm>.
University of Colorado at Boulder. (2013, September 24). 'Microbial clock' may help determine time of death. ScienceDaily. Retrieved September 1, 2015 from www.sciencedaily.com/releases/2013/09/130924153953.htm
University of Colorado at Boulder. "'Microbial clock' may help determine time of death." ScienceDaily. www.sciencedaily.com/releases/2013/09/130924153953.htm (accessed September 1, 2015).

Share This Page: