Casework testing of the multiplex kits AmpFℓSTR® SEfiler Plus™ PCR amplification kit (AB), PowerPlex® S5 System (Promega) and AmpFℓSTR® MiniFiler™ PCR amplification kit (AB)

The short tandem repeat (STR) kits SEfiler Plus™ (D3S1358, FGA, D8S1179, D18S51, D21S11, TH01, VWA, SE33, D2S1338, D16S539, D19S433 and Amelogenin), PowerPlex® S5 System (D18S51, D8S1179, TH01, FGA and Amelogenin) and MiniFiler™ (D13S317, D7S820, Amelogenin, D2S1338, D21S11, D16S539, D18S51, CSF1PO and FGA) were comparatively tested for their robustness and sensitivity. About 50 stains with highly degraded DNA and little DNA quantity served as examination material (e.g., hair with a telogen root, bones, degraded saliva stains on drinking vessels and skin cell mixtures).

The PowerPlex® S5 with five German DNA database (DAD) systems and the MiniFiler kit with four topical DAD systems and further STR markers show reduced amplicon lengths. The SEfiler Plus™ kit represents no MiniSTR multiplex, but contains the nine current DAD systems and further three systems D2S1338, D16S539 and D19S433, which are the potential expansion markers for the German DNA database.

We have found on the basis of our comparative stain investigations, that the SEfiler Plus kit was less sensitive than the PowerPlex® S5 and the MiniFiler kits. The MiniFiler™ and the PowerPlex® S5 kit showed comparatively high sensitivity.

Especially in analysing skin cell mixtures, the MiniFiler kit showed larger differences with regard to the performance of the fluorescent dyes/primer concentration co-ordination than the PowerPlex® S5. The SEfiler Plus kit generated – just as both MiniSTR kits – relative robust typing results, but there appeared an increased sensitivity for ‘allelic drop-outs’ and ‘imbalances’. Since the SEfiler Plus kit was not planned as MiniSTR concept, ‘allelic drop-outs’ were observed, as expected, more frequent in typing stains with degraded DNA and little DNA quantity, especially in the long polymerase chain reaction (PCR) products (e.g., D18S51).