An innovative approach for low input forensic DNA sample analysis using the GlobalFiler™ IQC PCR amplification Kit on the Magelia® platform

Abstract

Short Tandem Repeat (STR) markers have been the gold standard for human identification testing in the forensic field for the last few decades. The GlobalFiler™ IQC PCR amplification Kit has shown sensitivity, high power of discrimination and is therefore widely used. Samples with limited DNA quantities remain a significant hurdle for streamlined human forensic identification. Reaction volume reduction in a closed system paired with automation can provide solutions to secure DNA profiles when routine methods fall short. We automated and optimized the GlobalFilerTM IQC PCR Amplification Kit on the Magelia®, a closed molecular biology platform, to test whether reaction volume reduction in a confined automated system would improve signal and sensitivity. We evaluated the platform’s performance using reference and real casework samples (blood, cigarette butt, saliva and touch DNA) in the context of a 5-fold volume reduction when compared to the routine protocol. This strategy showed distinct advantages over standard treatment, notably increased signal for lower DNA inputs. Importantly, negative casework samples through routine treatment yielded “usable” DNA profiles after amplification using this strategy. This novel approach represents a first proof of concept for a method enabling users to treat limited samples, or to partition routine samples for multiple analyses.