Investigations into improving the standard DNA testing of trace samples at ESR

Abstract

ABSTRACTSince 2007, the Institute of Environmental and Science Research (ESR) has been using the AmpF/STR Identifiler profiling kit as the standard DNA test. Whilst this approach works well for most samples with a DNA input range of 400 pg to 2 ng, samples containing less DNA often have limited to no profiling success. If required, such samples can undergo testing using a more sensitive technique, such as mini-STR analysis or Low Copy Number (LCN) DNA analysis. The introduction of a more sensitive standard DNA test into the laboratory would likely prove to be greatly beneficial. Profiling success should increase, particularly for samples containing trace DNA concentrations, and the number of samples requiring rework and further analysis using an ultra-sensitive technique would potentially reduce. A number of new generation multiplex kits with increased sensitivity are now commercially available. One such kit is the AmpF/STR Identifiler Plus profiling kit, which has enhanced buffer formulation and an optimized PCR cycling protocol. This study investigates the profiling results from trace DNA samples using Identifiler at 28 cycles and Identifiler Plus, at 28 and 29 cycles, analysed using the 3500xL Applied BioSystems Genetic Analyzer. Any further benefits from including a post-PCR clean-up step and enhanced capillary electrophoresis conditions are investigated and discussed.