Modeling allelic analyte signals for aSTRs in NGS DNA profiles

Abstract

Points of view in this document are those of the authors and do not necessarily represent the official position or policies of their organizations.Names of commercial manufacturers are provided for identification purposes only, and inclusion does not imply endorsement of the manufacturer, or its products or services by the FBI.

An exploratory view into allelic drop‐out of sequenced autosomal STRs

“…where authors modeled allelic signals of sequenced data. Results indicated that locus‐specific variances could improve modeling of sequencing data based on different locus amplification efficiencies [39]. Additional data, as well as more variety in the sample profile of true biological samples would be of benefit to further evaluate the relationship between variables.…”

“…Further, these results suggest that evaluation should be performed considering the number, quality, and type of samples pooled together for sequencing when modeling allelic drop‐out and how these variables affect the optimal read count range, which is approximately 85,000 reads/sample with the ForenSeq™ DNA Signature Prep Kit [41, 42]. Degradation was found to also be important when modeling allelic drop‐out [39, 47]. Additionally, a quantitation cut‐off value may be useful to determine when to sequence a low‐level sample separately or with other lower‐level samples to optimize the amount of genetic data generated instead of batching with optimal level samples.…”

“…Additionally, progress toward addressing implementation of sequencing methods can be seen in updated guidelines from these organizations as well as research performed related to the topic of allelic drop-out [36][37][38][39][40].…”

“…Committees such as the Commission for International Society of Forensic Genetics have utilized this research to make recommendations or guidelines for interpretation and statistical analyses for crime scene profiles that show evidence of allelic drop‐out [32–35]. Additionally, progress toward addressing implementation of sequencing methods can be seen in updated guidelines from these organizations as well as research performed related to the topic of allelic drop‐out [36–40].…”

A comprehensive characterization of MPS-STR stutter artefacts

“…3) Marker efficiency: As provided by [61], we included locus-specific marker efficiency parameters. This was achieved by scaling the shape argument of the gamma distribution with a marker specific parameter.…”