NCJ Number
245548
Journal
Forensic Science International: Genetics Volume: 9 Dated: March 2014 Pages: 169-178
Date Published
March 2014
Length
10 pages
Annotation
This report presents findings from a developmental validation study of the capabilities and limitations of the PowerPlex 21 System, which is a short tandem repeat (STR) multiplex that has been optimized for casework samples while still being capable of database workflows that include direct amplification.
Abstract
The validation study found that the PowerPlex 21 System is a reliable assay with robust design. The genotyping of single-source samples was reliable across a range of template DNA concentrations with greater than 95 percent alleles called at 50 pg. Direct amplification of samples from FTA storage cards was successfully performed using the reagents provided with the system and modified cycling protocols provided in the technical manual. Mixture analysis showed that just over 95 percent of minor alleles were detected at 1:9 ratios. Reaction conditions were optimal and able to withstand moderate variations without affecting system performance. Reaction conditions included volume and annealing temperature as well as the concentrations of primers, DNA polymerase, magnesium, and Master Mix. Reproducible results were produced by different users at various sites. Concordance studies showed consistent results when comparing the PowerPlex 21 System with other commercially available STR-genotyping systems. PowerPlex loci represent all 13 core CODIS loci in addition to loci commonly used in Asia and Europe. 2 tables, 10 figures, and 34 references