Evaluation of Y-STR Data Using a Duplex Gender Real-Time PCR Assay on an ABI Prism 7000 SDS Followed by Amplification with Applied Biosystems AmpFLSTR Yfiler PCR Amplification Kit

Quantification is the process of determining the concentration of DNA in a sample and plays an extremely important role in the processes of amplification and STR typing. A method of quantification is mandated for a laboratory conducting forensic DNA analysis by National Standard 9.3 (1). Furthermore, anytime a forensic laboratory chooses to implement a new or novel methodology for any step in DNA analysis, a laboratory must conduct an internal validation to ensure the quality of method and any results generated on the equipment used within that laboratory are reliable, reproducible, and accurate before the method is utilized for casework analysis (1). Prior to an internal validation, the method or technology must undergo a developmental validation by the developer or manufacturer to determine conditions or limitations of the method or technology on DNA analysis of forensic samples (2). A study has shown that Y-STR results can be obtained even when the quantification of samples yields a value of 0.00ng/μl (4). The issue of the absolute lowest limit of detection in the quantification process versus input DNA concentrations of the unknown samples to yield any valuable Y-STR typing data has not been addressed. A duplex gender assay developed by Nicklas and Buel (3) has a reported detection limit of 0.5pg for the Alu probe of the duplex assay and quantification will be evaluated on a different qPCR platform than originally reported and followed by amplification using Applied Biosystems’ AmpFLSTR Yfiler PCR Amplification Kit to assess quantification limits. The goal of this internship project was to complete a preliminary evaluation of the sensitivity of a quantification methodology on a different qPCR platform under different detection parameters utilizing Y-chromosome DNA in correlation to Y-STR typing results and evaluate the data qualitatively.