Comparison of PowerPlex (TM) 16, PowerPlex (TM) 1.1/2.1, and ABI AmpflSTR (TM) Profiler Plus (TM)/COfiler (TM) for forensic use

Aim. Several amplification and detection formats for the analysis of short tandem repeat loci are readily available to the forensic laboratory. Carefu l consideration must be given to the throughput, sensitivity, concordance, data interpretation, facility requirements, and costs of operation. The Pen nsylvania State Police DNA Laboratory sought to establish that of any of th e amplification or detection formats generally used in the United States ge nerates concordant results and that the use of several formats within one l aboratory provides a solution to the interpretation of difficult evidentiar y samples. Methods. Validation work consisting of sensitivity, precision, mixture, and substrate studies was performed by use of each of three detection formats (ABI Prism((R))310 Genetic Analyzer, ABI Prism((R))377 DNA Sequencer, and t he Hitachi (FMBIOII)-I-(R) Fluorescent Scanner) and three amplification sys tems (GenePrint((R)) PowerPlex (TM) 16, GenePrint((R)) PowerPlex (TM) 1.1/2 .1, and Ampf/STR (TM) Profiler Plus/COfiler). The results generated in each of the formats were compared, along with the problems incurred. Results. All allele calls were concordant, with the exception of primer reg ion variants, and all detection systems were sensitive and reliable. Even w ith the use of multiple formats, a general protocol can be written with onl y one set of interpretation guidelines. Conclusion. National databases can be used with input data from any of thes e formats. The use of several detection formats al towed the forensic scien tist to select a system, based on sample quality, quantity, and throughput requirements. Interpretation issues resulting from complex mixtures, degrad ed samples, rare microvariants, internal primer variants, unusual heterozyg ote ratios, above or below ladder alleles, and potential tri-alleles can be verified.