Identifying, segregating, and analyzing male DNA in sexual assault and other evidence containing mixtures of male and female DNA presents a complex challenge. Due to the typically high quantities of female DNA encountered in sexual assault evidence, the ability to detect the minor male component in some samples may be limited using traditional autosomal short tandem repeat (STR) analysis. The use of a Y-STR testing system such as the AmpFℓSTR® Yfiler® PCR Amplification Kit may be required to detect and resolve the probative male profile.
Conventional quantification methods do not provide an efficient means to obtain a male to female DNA mixture ratio and direct downstream analysis to the optimal STR system. These methods can also overestimate the quantity of DNA present in a degraded sample, leading to unnecessary reruns and incomplete autosomal STR results. Critical investigative information can be missed if additional methods are not utilized.
The Quantifiler® Duo kit is a critical component of an improved and integrated workflow designed to enable laboratories to more effectively process sexual assault cases and other challenging mixture samples. The animated workflow diagram below illustrates how the kit functions as a "sample assessment system" which accurately determines the ratio of male to female DNA and guides selection of the optimal AmpFℓSTR® PCR Amplification Kit (autosomal, Y-STR or miniSTR) to maximize recovery of interpretable STR profiles.
Click here to download a printable version of this workflow diagram.
*Internal validation studies should be conducted to determine the values and thresholds to guide STR kit selection within each laboratory.