DNA profiles from fingermarks: A mock case study

Environmental factors and subsequent PCR inhibitors may affect the ability to retrieve DNA from handled objects. A poor quality DNA profile results from low DNA template or modifications imposed on the template (damage or degradation) prior to amplification. In this study, we show that direct PCR has the ability to amplify ‘touch’ DNA from uncleaned, handled, substrates following exposure to various environmental conditions. A variety of items (n = 90), ranging from metal cartridge cases, glass, tape and wood were touched briefly (less than 15 s) by 4 volunteers, exposed to the environment overnight, and in one case for 8 days, and tested for the presence of surviving DNA. Informative DNA profiles were obtained from 49 out of the 90 items (a success rate of 54%), with glass having the highest rate of DNA recovery.