Comparison of human DNA quantification kits based on a TaqMan assay

Human DNA quantiˆcation is an important step for subsequent short tandem repeat (STR) analysis and interpretation because it can provide various information on the quantity and quality for the extracted DNA. In this study, we compared four commercially available quantiˆcation kits based on a TaqMan assay and an intercalating-dye based quantiˆcation kit. The following three points were investigated: 1) variations of the average peak heights among individuals when 1 ng of DNA, the amount being determined by each quantiˆcation kit, was ampliˆed using GlobalFiler and Yˆler Plus PCR Ampliˆcation Kits, 2) eŠect of the presence of a female DNA on the quantiˆcation of male DNA, and 3) relationship between ``Degradation Index'' and the STR electropherograms. The average peak heights generated using GlobalFiler showed less individual-dependent variations in the four TaqMan based kits than the intercalating-dye based kit. The average peak heights generated using Yˆler Plus showed similar variations among the three TaqMan based kits capable of male DNA quantiˆcation along with total human DNA. The presence of a large amount of female DNA had little eŠect on male DNA quantiˆcation in all the three kits. When highly degraded DNA samples were quantiˆed, the ``Degradation Indices'' diŠered signiˆcantly among three kits. It was probably due to the diŠerent amplicon sizes of the long fragment targets among kits. Before implementing a new human DNA quantiˆcation kit in casework, it is essential to understand the characteristics of the adopted quantiˆcation kit.