A groundbreaking DNA forensics method is striving to establish a dependable way to gauge how much skin and other cells a suspect naturally sheds, which can then be compared to evidence found at crime scenes. This new approach uses a unique cell staining method that forensic scientists have applied while studying 100 individuals to assess the varying degrees of touch DNA shedding, ranging from minimal to substantial.
A groundbreaking DNA forensics method is striving to establish a dependable way to gauge how much skin and other cells a suspect naturally sheds, which can then be compared to evidence found at crime scenes.
Utilizing an innovative cell staining technique developed at Flinders University, experts in forensic science evaluated 100 individuals to understand how they shed different amounts of touch DNA, from minimal to significant levels.
Professor Adrian Linacre from the College of Science and Engineering notes, “Our most recent study indicates that males generally shed more DNA, releasing a greater number of cells per square millimeter compared to females.”
He also mentioned, “There was no observable difference in the number of cells shed from the right or left thumbs, indicating that it doesn’t matter which hand is used to hold an object.”
This research builds on a preliminary study from three years ago and intends to create a new pathway for identifying criminals, including those who may not shed DNA effectively.
Professor Linacre speculates that suspects linked to a crime through DNA may eventually claim, “But I naturally shed a lot of DNA.”
Out of the 100 participants, 98 demonstrated consistent and reproducible cell shedding levels, confirming that individuals release the same quantity of cells regardless of when samples are collected.
The current study marks a step forward in creating a reliable, straightforward, and economical test for determining a suspect’s “shedder status.” This could serve as an additional tool for DNA profiling and assessing the amount of time someone may have been at a crime scene, which could potentially shorten investigation durations and decrease the chances of conflicting DNA evidence.
“Knowing what type of ‘shedder’ someone is can help investigators understand how likely an individual is to leave behind DNA on an item through touch,” Professor Linacre explains.
This information could aid in calculating a likelihood ratio to determine the chances of a person’s DNA being found on an item.
Researchers emphasize that further work is needed to refine the assessment of shedder status.
The recent research that expanded on shedding experiments was initiated by Flinders PhD candidate Dr. Piyamas (Kanokwongnuwut) Petcharoen and received support from the Attorney-General’s Department through Forensic Science SA and the Ross Vining Memorial Research Fund.
Dr. Petcharoen, who currently works at Suranaree University of Technology in Thailand, is a co-author of the new study published in Forensic Science International: Genetics, alongside colleagues from Flinders University, including Madison Nolan, Professor Paul Kirkbride, and Professor Linacre.
