Prediction of the appropriate amount of degradated human DNA template for PCR using Quantifiler Trio DNA Quantification Kit

Abstract

 Forensic samples left at crime scenes are exposed to various environmental factors, and the extracted DNA from them are sometimes highly degraded. It is difficult to set an amount of degraded human DNA template, and allelic drop-outs may occur after PCR amplification and electrophoresis, making STR analysis difficult. In order to obtain useful STR results, it is necessary to know the degree of human DNA degradation in addition to accurate human DNA quantification. In this study, we examined the relationship between the Degradation Index provided by the Quantifiler Trio DNA quantification Kit and the allele detection rate, using degraded DNA prepared by two methods. The amount of the human DNA artificially degraded by NEB Next dsDNA Fragmentase or UV irradiation were determined based on the small autosomal human target of the DNA quantification kit and STR test was performed using the GlobalFiler and Yfiler Plus PCR Amplification Kit. The ski-slope effect profiles in the electropherograms were observed and some alleles of high molecular weight locus were not detected. The large differences in the Degradation Index values and the allele detection rates were observed between the two degradation methods. When the DI was greater than 2.0 for fragmented DNA and 5.61 for UV-irradiated DNA, not all alleles were able to be detected even with 1 ng of DNA template.