Evaluation of Eight Commercially Available STR Kits - Technology Evaluation

• NCJ Number: 234049
• Author(s): National Forensic Science Technology Center
• Date Published: February 2008
• Length: 15 pages
• Agencies: NIJ-Sponsored
• Award: FY2008 Forensic Technologies Center of Excellence

Annotation

In order to assist forensic DNA analysts in their assessment of the performance of commonly used short-tandem-repeat (STR) amplification kits, the National Forensic Science Technology Center (NFSTC) evaluated the performance of eight STR amplification kits: Applied Biosystems’ Ampf&STR® Profiler Plus ID® kit, Cofiler® kit, Identifiler® kit, MiniFiler™ kit and Yfiler® kit, and Promega’s PowerPlex® 16 system, PowerPlex® Y system and PowerPlex® S5 system.

Abstract

The kits were assessed for sensitivity, peak ratios at heterozygous loci, baseline noise, stutter ratio, and amplification artifacts. The evaluation found that PowerPlex® 16 exhibited greater sensitivity than Identifiler®, Profiler Plus® and Cofiler® and MiniFiler™ exhibited greater sensitivity than PowerPlex® S5. Identifiler®, Profiler Plus®, and Cofiler® demonstrated comparable peak heights to each other for each concentration. All of the amplification kits, with the exception of PowerPlex® 16, maintain a 60 percent heterozygosity ratio for 1 ng and 0.5 ng concentrations. Identifiler® maintained heterozygosity ratios of 60 percent more frequently than PowerPlex® 16 for concentrations from 0.0625 ng to 1 ng. Profiler Plus® and Cofiler® maintained heterozygosity ratios more frequently than Identifiler®, for the lower concentrations in the dilution series (0.078 ng to 0.125 ng). PowerPlex® Y displayed higher RFU range than Yfiler® at each concentration. Cofiler®, Identifiler® and PowerPlex® S5 displayed less stochastic effects when compared to kits of similar size. The mixture sample with a 1:5 ratio yielded a full profile for the minor donor for all amplification kits except PowerPlex® Y. Cofiler® and PowerPlex® S5 are the only two kits that displayed a full profile for the minor donor down to 1:8 ratio. Areas for improvement in the eight kits are outlined, and training requirements and health and safety issues are discussed. 5 figures