The software also provides gender information (Electronic Supplementary Material Fig. 3). The sensitivity and precision of the DNA Detection and Gender
Identification functions were assessed by analysing five purified extracted genomic DNA samples over a range of DNA input amounts (4 ng, 3 ng, 1 ng, 500 pg, 250 pg, 62.5 pg). These inputs represent the total amount of template added across the four assay tubes with each tube amplifying one quarter of the stated amount. Six replicates were analysed at each DNA input amount and an additional 30 No Template Control (NTC) samples were also analysed. The DNA was added to each reaction plate prior to dispensing the ZD1839 manufacturer required volume of reaction mix. All samples used were obtained from the Health Protection Agency Typed Collection and quantified (Promega Plexor® HY: DC1001) and standardised to a concentration of 1 ng/μl before
dilution. The accuracy and sensitivity of the ParaDNA System was assessed selleck products by performing a mock case sample study. Samples tested were 10 μl blood on glass (n = 20), 10 μl blood on concrete (n = 17), 50 μl saliva on cotton (n = 22), tools handled for 5 minutes (n = 25), latex gloves worn for 10-20 minutes (n = 30) and fingerprints on glass after donors rubbed their fingertips together for 1 minute (n = 28). Samples were chosen to represent a range of template levels and were collected from LGC Forensics’ staff members with the donor’s consent. All mock samples underwent ‘indirect sampling’ with Methane monooxygenase evidence items being wet and dry swabbed using rayon swabs (Fisher Scientific: DIS-255-065 N) following an LGC Standard Operating Procedure (SOP) before sub-sampling from the wet swab using the ParaDNA Sample Collector. Collection from the swab, rather than directly from the item served to standardise the test substrate and enabled the user to sub-sample within 60 seconds. In the process of sampling, the swab head fibres were teased apart increasing the surface area of the swab head and thereby encouraging more cellular material to
be collected. A control group of items that underwent no ParaDNA sampling were wet and dry swabbed only to assess what impact the ParaDNA collection process had on the level of available template for subsequent laboratory DNA analysis. This group comprised of blood on glass (n = 19), blood on concrete (n = 18), saliva on cotton (n = 23), touched tools (n = 23), latex gloves (n = 42) and fingerprint on glass (n = 42). All swabs were sent to the LGC Scene of Crime DNA operations unit for extraction (Qiagen QIAsymphony DNA Investigator chemistry: 952034) and quantification (Promega Plexor® HY: DC1001). Items sampled with the ParaDNA Sample Collector that subsequently yielded DNA with a measured concentration of less than 50 pg/μl also underwent subsequent STR amplification (Applied BioSystems/Life Technologies AmpFlSTR® SGM Plus® system: 4307133) and separation by CE (Applied BioSystems/Life Technologies, ABI3100xl).