FORENSIC SCIENCE experts are going into an innovative counter-terrorism technique that checks for environmental DNA in the dust on clothing, baggage, shoes or even a passport. The research developed a system to trace the source of dust on suspect articles to match a soil profile of a specific area or overseas country.
This could help provide evidence of where a person of interest might have travelled based on the environmental DNA signature from dust on their belongings. The microscopic evidence, based on soil geochemical, bacterial and fungal analysis would complement and enhance current forensic intelligence tools.
Scientists say environmental samples serve as ideal forms of contact trace evidence as detection at a scene can establish a link between a suspect, location and victim. Environment samples extracted via the ‘massively parallel sequencing’ technology provide biological signatures from complex DNA mixtures and trace amounts of low biomass samples.
The intelligence and forensic potential of dust traces for counter-terrorism and national security will put the new technique on trial with soil reference data from across Australia provided by partner Geoscience Australia.
This project will utilize a series of soils with contrasting properties to understand the relationship between soil biogeochemical signals and the derived dust signal under controlled conditions, before introducing environmental variables through an ‘in-situ’ experiment.
Forensic science researchers are building a lot of new insights into crime scene investigation – including the difference between high, intermediate and low skin shredder that will help in the understanding of trace or ‘touch DNA’.
The latest research, ‘DNA deposited in whole thumbprints’, further studies inter-variation of DNA shedding obtained from experiments on samples gathered from different people and their thumbprints.
This study allows a growing understanding of differences in DNA ‘shedding’ between people, and why traces of people’s DNA can be found a long time after an event.
It has also been found that some people have higher intra-variability, indicating that these individuals will not always reliably pass on similar amounts of cellular material and DNA.
Any new data on cell deposition goes to strengthen the understanding of how cells are deposited and why some are found well after a criminal event. The study used a nucleic acid binding dye that shows the number of cells deposited when a person touches an object.
The latest work leads to more reliable touch DNA collection methods, which can be key in forensic casework. Researchers look forward to producing more accurate methods and informative research to help forensic scientists to fulfill their roles in a challenging environment. By Manny Palomar, PhD (EV Mail January 23-29, 2023 issue)
