Following the transfer of DNA: How far can it go?

Following the transfer of DNA: How does the presence of background DNA affect the transfer and detection of a target source of DNA?

“…This background material may affect the transfer of the target biological material, and therefore also have an impact on the detection of the target DNA. This study extends the aims and design of Lehmann et al [20] by investigating the influence of different background biological materials (wet blood, dried blood, and touch DNA) on the transfer and detection of a target source of different biological materials (wet blood, dried blood, and touch DNA) after multiple transfer steps. The two substrates used are glass and cotton fabric.…”

“…However, only a limited number of studies have considered multiple transfer steps, and the correlation between secondary transfer and tertiary, quaternary or further transfer scenarios [10,17,19,20]. Despite there being a limited number of studies designed to consider the possibility of multiple transfer steps of DNA, one study from Lehmann et al [20] showed that DNA transfer beyond the second transfer step was possible, depending on the specific combination of contact type, substrate and biological materials involved. In Lehmann et al [20], the substrates to which a specific source of DNA, referred to as "target DNA," was transferred step by step were free of background biological material.…”

“…Despite there being a limited number of studies designed to consider the possibility of multiple transfer steps of DNA, one study from Lehmann et al [20] showed that DNA transfer beyond the second transfer step was possible, depending on the specific combination of contact type, substrate and biological materials involved. In Lehmann et al [20], the substrates to which a specific source of DNA, referred to as "target DNA," was transferred step by step were free of background biological material. However, in many scenarios it is likely that the substrates on which the target DNA is deposited will contain some background biological material.…”

“…The two substrates used are glass and cotton fabric. The experimental design comprised five transfer steps after initial deposit, and was conducted following the protocol described in Lehmann et al [20]. The background biological materials deposited on the substrates were either (i) all from the same individual, who was different from the depositor of the target DNA on the initial substrate; or (ii) was from a different individual on each substrate within a sequence of multiple transfer steps.…”

Evaluation of collection and extraction methodologies of latent fingerprints for military application

“…Glass and metallic surfaces were represented by glass microscope slides [3] and these slides wrapped in aluminum foil. All of them were pre-cleaned with 10% bleach and 70% ethanol solutions and UV irradiated for 20 min prior to the experiment.…”