Degrading DNA profiles to a specific level using UV exposure

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ABSTRACT

Generating degraded DNA samples can be useful for forensic DNA research as this can mimic the condition of crime scene samples and results from such samples. Methods which use quick and cost-effective ultraviolet light (UV) exposure can be utilized to degrade DNA but are not well documented. This study aimed to establish a procedure and define the parameters required to generate Short Tandem Repeat (STR) profiles at different degradation levels. UV exposure times between 0 and 60 s were tested using genomic and control DNA. Sample eluates were quantified with Quantifiler^TM Trio pre- and post-UV exposure, and select samples were profiled using PowerPlex® 21. Quantification data and STR profiles were analysed to identify metrics which indicated degradation severity. Samples were observed to be degraded by UV exposure as evidenced by established DNA degradation markers. No specific metric was identified to reliably determine the severity of sample degradation, but it was noted that UV exposure between 5 and 10 s resulted in mild degradation, between 15 and 25 s generated moderate degradation, and between 45 and 60 s resulted in severe degradation in STR profiles. This study indicates that quantification before and after UV exposure may be useful to estimate the degree of degradation via one quantification target.

KEYWORDS:

• DNA degradation
• UV exposure
• forensic DNA
• DNA damage

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the NSW Health Pathology.