Evaluation of a fluorescent dye to visualize touch DNA on various substrates

Abstract

The ability to visualize the presence of cellular material deposited by touch onto items of forensic importance has the potential to greatly aid in criminal investigations. It is now routine in forensic casework to examine items for DNA assumed to have been deposited by touch [1-3]. Such DNA is often referred to as 'touch DNA' even though samples collected from such deposits can also include DNA from undetermined biological sources other than that derived from skin and/or background DNA from actions other than touching [4]. Visualizing the location of cellular material, and therefore the source of DNA, will allow examiners to target sampling to areas where DNA is present, and not sample areas where DNA is absent.Without knowledge of cellular material location, collection of DNA,

Recent advances in forensic biology and forensic DNA typing: INTERPOL review 2019–2022

“…DNA losses were quantified with mock fingerprints deposited on four different surfaces to better understand DNA collection and extraction method performance [ 189 ]. The application of Diamond Dye has been shown to enable visualization of cells deposited on surfaces without interfering with subsequent PCR amplification and DNA typing [ [190] , [191] , [192] ].…”

Interpol review of fingermarks and other body impressions (2019 – 2022)

“…Visualisation of touch DNA – Several papers referred to Diamond™ Nucleic Acid Dye to emphasize the genetic material contained in fingermarks [ [469] , [470] , [471] , [472] , [473] , [474] , [475] , [476] ]. Some ridge details could be observed, but this approach was mostly presented to emphasize areas of interest or investigate shedder status.…”

Monitoring cell loss through repetitive deposition

“…The use of fluorescent nucleic acid staining dyes (e.g., Diamond™ dye, SYBR® Green I, and GelGreen™) has been developed recently for detecting latent DNA on items [5,[11][12][13][14][15][16]. A recent study reported monitoring the deposited cell number within entire thumbprints on a glass slide through a "single touch" event using DD staining [6]; however, a comparison of the visualized cells number from the entire and a part of the thumbprint was not part of this report [6].…”