This study compared the performance of a relatively new STR kit in the US market (Investigator 24plex QS kit; Qiagen) with the GlobalFiler PCR Amplification kit (Thermo Fisher Scientific) when genotyping highly inhibited and low level DNA samples.
In addition, DNA (1 ng and 0.1 ng input amounts) was spiked with various concentrations of five inhibitors common to human remains (humic acid, melanin, hematin, collagen, calcium). Furthermore, bone (N = 5) and tissue samples from decomposed human remains (N = 6) were used as mock casework samples for comparative analysis with both STR kits. In cases such as mass disasters or missing persons, human remains are challenging to identify as they may be fragmented, burnt, been buried, decomposed, and/or contain inhibitory substances. GlobalFiler PCR Amplification kit (Thermo Fisher Scientific) when genotyping highly inhibited and low level DNA samples. The data from the current study suggest that the GlobalFiler kit may be slightly more sensitive than the Investigator kit. On average STR profiles appeared to be more balanced and average peak heights were higher when using the GlobalFiler kit; however, the data also show that the Investigator kit may be more tolerant to common PCR inhibitors. Although both STR kits showed a decrease in alleles as the inhibitor concentration increased, more complete profiles were obtained when the Investigator kit was used. Of the 11 bone and decomposed tissue samples tested, 8 resulted in more complete and balanced STR profiles when amplified with the GlobalFiler kit. (publisher abstract modified)
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Date Published: May 1, 2018