Non-self DNA on the neck: a 24 hours time-course study
Chiara Fantinato, Peter Gill, Ane Elida Fonneløp
Abstract
Non-self DNA is normally present on skin due to DNA transfer occurring during daily activities. The understanding of persistence and accumulation of foreign DNA on the neck can assist in the interpretation of DNA evidence collected from an assaulted victim. Establishing the composition and level of non-self DNA present is relevant, especially in cases where the victim cohabits with other individuals, such as partner and children. This study investigated the persistence and accumulation of non-self DNA on the neck, over the course of 24 h. DNA samples were collected from the neck of 20 adult volunteers at three time-points, on two days. The detection of a partner's DNA and DNA from unknown sources was studied in relation to the living arrangement and to the activities performed by each individual. An increased number of non-self alleles were detected over time. Partner's DNA was observed to accumulate during the day and to persist when an individual was absent from the shared home environment. DNA from unknown contributors was found on the neck of individuals that used public transport, attended public spaces and had social interactions. The data acquired from this study will help to increase knowledge on the composition of DNA present on an individual's neck in a daily situation.