DNA transfer by different parts of a hand

© 2017 Elsevier B.V. Hands are a major vector for transfer of DNA detected at crime scenes. The DNA profiles generated from touched objects are interpreted in respect to the person of interest's association with the criminal event and/or crime scene. Different parts of a hand will contact different items in different ways. In some circumstances it may be relevant to have an awareness of similarities and differences in: DNA yields, proportional contributions to mixture profiles, and transfer, from different parts of a hand. This preliminary study analyses DNA quantities and contributing origins of profiles generated from 14 different areas of a hand, and a corresponding handprint, after contact with a glass plate coated with dried saliva of a known individual, followed by contact with a DNA-free glass plate leaving the handprint. This was replicated by four individuals. Within the conditions of this test, different parts of a hand appear to have proportionally more DNA, more non-self DNA, and may be more likely to pick-up and transfer non-self DNA, than others (especially fingertips relative to other hand parts). This knowledge may be important when prioritizing samples to be targeted and when interpreting DNA profiles from an activity level perspective. This study also identified improvement opportunities in experimental design to enhance the value of future studies of this type.