A new strategy for a “direct” amplification of forensic samples

One of the most effective ways for human identification is the genetic analysis of the crime scene biological evidence(s). However, such studies could be expensive, and it could take too long before the genetic profile is finally obtained (1). In the present work, we have made modifications to the conventional DNA extraction protocol (1), in order to perform a "direct" amplification, trying to obtain the optimal conditions for generating a fast and reliable genetic profile. In order to do so, we employed different fresh blood and saliva samples, and carried out an extraction with the Prep-n-Go (TM) buffer (ThermoFisher (TM) Scientific, Foster City, USA) during 30 s of incubation. Then the extract was collected to perform the autosomal amplification with GlobalFiler (TM) Express PCR Amplification Kit (ThermoFisher (TM) Scientific, Foster City, USA). The quality of the new procedure always took into account the minimum standards of quality, estimated by the allele's height in RFUs. On the other hand, the aptitude of our newly proposed protocol to keep the required quality, performing sensibility, reproducibility and contamination tests was evaluated. We were able to conclude that it was possible to obtain a reliable genetic profile performing a "direct" amplification, although the best amplification conditions varied according to the type of sample. In general, the best obtained results were determined in a range of 1 mu l extract volume, and it was possible to obtain a genetic profile in 90 min.