Non-self DNA on the neck: a 24 hours time-course study

Area of Science:

• Forensic Science
• Human Biology
• Genetics

Background:

• Non-self DNA transfer occurs daily on skin.
• Understanding foreign DNA on the neck aids interpretation of forensic evidence, especially in cohabiting households.

Purpose of the Study:

• To investigate the persistence and accumulation of non-self DNA on the neck over a 24-hour period.
• To correlate DNA detection with living arrangements and daily activities.

Main Methods:

• Collected neck DNA samples from 20 adult volunteers at three time-points over two days.
• Analyzed partner's DNA and unknown DNA sources in relation to lifestyle factors.

Main Results:

• An increase in non-self DNA alleles was observed over time.
• Partner's DNA accumulated during the day and persisted even when away from home.
• Unknown DNA was detected on individuals using public transport, public spaces, or engaging in social interactions.

Conclusions:

• Daily activities lead to the accumulation and persistence of non-self DNA on the neck.
• Findings enhance understanding of DNA evidence composition in real-world scenarios.
• This research provides valuable data for forensic casework involving neck DNA.