NCJ Number
254584
Date Published
March 2019
Length
12 pages
Annotation
This is the Final Summary Overview for a project with the goal of characterizing STR alleles from a large U.S. cohort and developing an online database (the POPSeq Human STR Sequence Diversity Database).
Abstract
Next-generation sequencing (NGS), also called massively parallel sequencing (MPS), is rapidly evolving and creating new possibilities for more sensitive methods of genetic typing of forensic samples. This technology enables high samples and genetic marker multiplexing of conventional forensic loci and investigative data. Sequencing STRs using NGS has enabled the identification of STR isoalleles, sequence variants that do not differ by size (length), but do differ in the underlying sequence. The forensic community is eager to use this additional sample variation in instances where traditional capillary electrophoresis has limited interpretation, such as complex mixtures and degraded samples; however, no comprehensive resource has existed that compiles allele frequencies of sequence-based STR loci across multiple populations. In the current project, the complete population study analyzed autosomal STR loci for approximately 900 samples, and frequencies were calculated based on sequence composition. Overall, sequence-based allelic variants (isoalleles) were observed in 20 out of 22 STR loci commonly used in forensic DNA genotyping, with the highest number of isoalleles observed in locus D12S391. Although the population data will be published in a forensics journal and deposited with the online STR database, STRidER, the POPSeq database cannot continue without funding. A continuation grant was proposed to the FY18 Research and Development in Forensic Science for Criminal Justice Purposes, but was not selected; consequently, the website was discontinued on December 31, 2018, at the end of this grant. 1 figure and a listing of work products
Date Published: March 1, 2019