Evaluating the performance of whole genome amplification for use in low template DNA typing

We report on the performance of two whole genome amplification methods, GenomiPhi™ amplification and modified-improved primer extension preamplification (mIPEP), when analysing low template DNA samples. Template as low as 10 pg treated with mIPEP generated more than 1 ng of DNA that could be used in STR typing. Initial templates of 100-10 pg, when treated with mIPEP, generated an increase in alleles compared with control samples. Partial profiles using the AmpFℓSTR(®) Identifiler™ Kit were produced from this suboptimal DNA template, with 70% of the possible alleles (21.7 ± 2.1 in 32 alleles) recorded, using the mIPEP amplified products with an initial template of 100 pg. Allelic imbalance decreased with samples treated with whole genome amplification method (WGA) compared with those without this initial treatment. Further methods for improvement were also analysed including altering the condition of electrokinetic injection, and the successful DNA typing rate was increased to about 80%. This report illustrates the potential use and limitations of WGA for low template samples.