Researchers are exploring a new way to measure DNA shedding that could be helpful in criminal investigations.
Every person sheds different levels of DNA into environment through coughing, flushing, and, desquamation (peeling or flaking) and a method to measure this is expected to help police officials catch criminals.
In this way, researchers at Flinders University tested a novel forensic technique of cell staining on 100 volunteers to confirm how people shed varying levels of touch DNA, from very low to very high.
Method can one day reduce investigation timeframes
Stemming from a pilot study three years ago, the study focuses to develop a new avenue to track down criminals – including evidence from people who might be ‘poor shedders’.
Of the 100 participants in the study, 98 showed consistent and reproducible cell number deposition – showing people shed the same cells ‘no matter when’ samples are taken, according to the study .
The new study makes progress to develop a robust, simple and affordable test of a suspected perpetrators’ ‘shedder status’ as an additional means of DNA profiling and testing the possible time spent at a crime scene.
This can one day reduce investigation timeframes, and reduce the possibility of conflicting DNA evidence.
Males are more prolific at shedding in general
“Our latest study also shows that males are more prolific at shedding in general, depositing more cells per square millimeter than females,” said Professor Adrian Linacre, from the College of Science and Engineering.
“Also there was no difference in the deposition of cells between right and left thumbs, so it doesn’t matter if an item is held in someone’s right or left hand.”
The study also found that shedder status remains constant 30 minutes after handwashing.
No difference between the cells deposited by the left and right thumbs
Published in the journal Forensic Science International Genetics , the study found that there was no difference between the cells deposited by the left and right thumbs in 13 of the 15 individuals tested. This study based on 100 individuals strongly suggests that shedder status is a continuum phenomenon.
The study maintained that inter-laboratory trials are needed to assess whether cell scoring between persons and institutes record persons consistently in terms of shedder type.
Comparison between methods is also needed to determine whether individuals change shedder type based on the tests performed.
No agreed test to determine a person’s shedder type
Currently, there is no agreed test to determine a person’s shedder type and only by large scale sampling and covering as many factors as possible will there be a recommended shedder test, according to the study .
“Depending on what type of ‘shedder’ a person is, confirmation of their shedder status can guide investigators as to the propensity of an individual to pass on their DNA to an item via touch contact with the hand,” explained Linacre.
“This information can be used in a likelihood ratio to evaluate the probability of finding a person’s DNA on an item.”
However, researchers have underlined that more efforts are needed to find the best way to assess shedder status.
Most Popular
Comments / 0