A large-scale dataset of single and mixed-source short tandem repeat profiles to inform human identification strategies: PROVEDIt

Abstract

DNA-based human identity testing is conducted by comparison of PCR-amplified polymorphic Short Tandem Repeat (STR) motifs from a known source with the STR profiles obtained from uncertain sources. Samples such as those found at crime scenes often result in signal that is a composite of incomplete STR profiles from an unknown number of unknown contributors, making interpretation an arduous task. To facilitate advancement in STR interpretation challenges we provide over 25,000 multiplex STR profiles produced from one to five known individuals at target levels ranging from one to 160 copies of DNA. The data, generated under 144 laboratory conditions, are classified by total copy number and contributor proportions. For the 70% of samples that were synthetically compromised, we report the level of DNA damage using quantitative and end-point PCR. In addition, we characterize the complexity of the signal by exploring the number of detected alleles in each profile.

The efficacy of DNA mixture to mixture matching

“…Six each of two-, three-, four-, and five-person GlobalFiler™ mixtures from the publicly available PROVEDIt dataset [11] were analysed in GeneMapper® ID-X version 1.5 following Kelly et al [12]. The mixtures were selected so that where possible half of them shared common contributors and the other half did not.…”

“…assuming Hardy-Weinberg equilibrium and linkage equilibrium). The PROVEDIt dataset [11] was constructed to consist of mixtures with donors originating from different and unspecified ethnicities. In practice the true ethnic composition of crime scene samples is also not known and different contributors may have different or perhaps mixed ethnicities.…”

Evaluating the Recovery of DNA from Adhesive Tape after Exposure to Heat and Humidity: Assessing the Degradation Index and STR Profile

“…Genetic Analyzer and the GlobalFiler TM STR multiplex 24 . The known genotypes for all participants were also provided.…”

“…Alfonse et al utilized the PROVEDIt Database to assess the degradation of an STR profile at a threshold of 1 RFU by modeling the sloped contour of the STR profile by the exponential decay in fluorescence as a function of molecular weight using the following equation: = ̅ , where is the sum of the peak heights associated with the known genotypes at locus , ̅ is the average base pair size of the STR alleles at locus , and and are the exponential parameters obtained for each sample using least squares regression 24 . In a highly degraded sample, the larger molecular weight STR fragments exhibit lower peak heights compared to the smaller molecular weight STR fragments which causes to be a large negative value 24 . If there is minimal or no degradation present, the peak heights will be more balanced across all loci in the sample and will be near zero 24 .…”

“…In a highly degraded sample, the larger molecular weight STR fragments exhibit lower peak heights compared to the smaller molecular weight STR fragments which causes to be a large negative value 24 . If there is minimal or no degradation present, the peak heights will be more balanced across all loci in the sample and will be near zero 24 . Untreated samples were found to have a Quantifiler TM Trio DI near one and near zero 24 .…”