Improving results from touch DNA evidence with optimized direct PCR methods

Improved methods to generate high-quality DNA profiles from touch DNA samples are of considerable interest to forensic DNA laboratories. Direct polymerase chain reaction (PCR) amplification, a sample processing method in which samples are added directly to amplification reactions without prior purification or quantification, has been identified as a method that may improve the generation of genotyping data from such samples; however, laboratories in the United States are required to use standard DNA processing methods to process low-level sample types. In part, this is due to FBI Quality Assurance Standard (QAS) 9.4, which requires all unknown forensic samples to undergo human-specific DNA quantification prior to amplification of short tandem repeat (STR) loci. The goal of this 3-year study was to generate data in support of a reevaluation of QAS 9.4.
In two phases, this study examined the following: direct PCR-compatible collection methods in conjunction with mock touch DNA evidence sa..., The following data are provided for each sample: Quantifiler Trio small autosomal DNA concentration (ng/μl), Quantifiler Trio large autosomal DNA concentration (ng/μl), DNA yield, Quantifiler Trio degradation index (DI) value, FI value, peak height (RFU) for alleles at each locus, the number of alleles obtained, the number of alleles expected, the number of original CODIS core loci obtained, random match probability (RMP), and CODIS eligibility (yes/no). Allele calls are not provided to protect the privacy of the donors.
Forensic DNA profile index (FI): A quality score between 0.05 and 10 was also assigned to each profile based on the FI developed by Hedman et al. The FI provides a quantitative quality score for each DNA profile by taking three factors into consideration: overall peak height, peak height balance within each locus in a profile, and the profile balance across all loci of a profile. A score of 10 indicates a DNA profile of the highest quality, whereas a score of 0.05 indic..., Phase I and Phase II datasets are provided as .xslx and .csv files.