Abstract
DNA isolation for PCR-based short tandem repeat (STR) analysis is essential to recover high yields of amplifiable DNA from low copy number (LCN) DNA samples. There are different methods developed for DNA extraction from the small bloodstain and gloves, commonly found at crime scenes. In order to obtain STR profiles from LCN DNA samples, DNA extraction protocols, namely the automated $iPrep^{TM}$ $ChargeSwitch^{(R)}$ method, the automated $QIAcube^{TM}$ method, the automated $Maxwell^{(R)}$ 16 DNA $IQ^{TM}$ Resin method, and the manual $QIAamp^{(R)}$ DNA Micro Kit method, were evaluated. Extracted DNA was quantified by the $Quantifiler^{TM}$ Human DNA Quantification Kit and DNA profiled by $AmpFISTR^{(R)}$ $Identifiler^{(R)}$ Kit. Results were compared based on the amount of DNA obtained and the completeness of the STR profiles produced. The automated $iPrep^{TM}$ $ChargeSwitch^{(R)}$ and $QIAcube^{TM}$ methoas produced reproducible DNA of sufficient quantity and quality trom the dried blood spot. This two automated methods showed a quantity and quality comparable to those of the forensic manual standard protocols normally used in our laboratory. In our hands, the automated DNA extraction method is another obvious choice when the forensic case sample available is bloodstain. The findings of this study indicate that the manual simple modified $QIAamp^{(R)}$ DNA Micro Kit method is best method to recover high yields of amplifiable DNA from the numerous potential sources of LCN DNA samples.