By John Ross – The Australian 23 Dec 2016
Higher Eduction Report Sydney @JohnRoss49
The balance of bugs in the body is crucial to quality of life. Now scientists are turning to bugs to get a better measure of death.
US researchers have found that the “microbiome” — the bacteria and other microbes living in and on people’s bodies — provides a surprisingly accurate gauge of how long they have been dead.
They say the discovery could sharpen forensic methods, shedding new light on murder investigations and corroborating or disproving alibis.
The team based its findings, outlined in the journal PLOS ONE, on DNA analyses of bacterial swabs from 21 bodies at various stages of decomposition. They used a “machine learning” approach to develop an algorithm equating microbial composition to time since death.
Team leader Nathan Lents said while it was a proof-of-concept study, the results had exceeded expectations.
“In a few years we’ll have a good idea of how to use this in forensic applications,” said Professor Lents, a molecular biologist with City University of New York. Recent research has uncovered links between the microbiome and Parkinson’s disease, bowel cancer, mental illness and autism, with microbes in the gut even harvested for new antibiotics.
Professor Lents said existing methods of determining time of death were accurate to within about six hours for the first two days after life.
From then on they mainly depended on analyses of insects in dead bodies, yielding “solid guesses” that often ranged over a few days.
“Beyond a week, no one really trusts the methods,” he said.
The new approach could estimate time of death to within about two days, even after four weeks of decomposition.
Microbiome analysis could also supply information such as a victim’s drug use, “even when the traces of the drug itself are long gone”.
He said it could possibly help determine cause of death or provide insights into places victims had recently visited.
In a study published last month, Californian researchers showed microbes on people’s mobile phones could be used to help identify their owners.
Original article here