Forensic scientists improve touch DNA collection methods

Skin cells and their DNADNA, or Deoxyribonucleic Acid, is the genetic material found in cells, composed of a double helix structure. It serves as the genetic blueprint for all living organisms. Read Full Definition varies between individuals, but new dataInformation in analog or digital form that can be transmitted or processed. Read Full Definition shows that some groups of people have higher variability in their cell deposits. The South Australian forensic scienceDiscover the fascinating field of Forensic Science, the application of scientific principles to legal matters. This post delves into its many disciplines, from DNA analysis to crime scene investigation, its importance in the justice system, Read Full Definition researchers are building a suite of new insights into crime scene investigation — including the difference between high, intermediate and low skin ‘shedders’ that will help understanding of trace or ‘touch DNA’.

The latest research, ‘DNA deposited in whole thumbprints’ (just published in Forensic Science International: Genetics), further studies inter-variation of DNA shedding obtained from experiments on samples gathered from 10 different people and 30 of their thumbprints.“The first challenge at a scene is finding touch DNA, which is why we have developed an accurate special aerosol fluorescent dye ‘marker’,” says Professor Adrian Linacre, who leads Flinders University’s forensic DNA technology research group.“A further challenge is evaluating the value of the evidenceEvidence is any form of proof, such as objects, materials, or scientific findings, presented to establish or disprove a fact in a legal proceeding. It is used to reconstruct events and link or exclude individuals Read Full Definition, and that’s where shedders are a factor.“Data like this new study allows a growing understanding of differences in DNA ‘shedding’ between people, and why we might find traces of people’s DNA a long time after an event.”Flinders University PhD candidate Todd Kaesler says: “We have 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. This is individual-dependent.“Any new data on cell deposition goes to strengthen our 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.

“Our work leads to more reliable touch DNA collection methods, which can be key in forensic casework,” says Professor Linacre.

“We look forward to producing more accurate methods and informative research to help forensic scientists to fulfil their roles in a challenging environment.”

Journal Reference: Todd Kaesler, K. Paul Kirkbride, Adrian Linacre. DNA deposited in whole thumbprints: A reproducibility study. Forensic Science International: Genetics, 2022; 58: 102683 DOI: 10.1016/j.fsigen.2022.102683