New forensic testing kit from Applied Biosystems helps improve DNA analysis in sexual assault cases

Applied Biosystems, an Applera Corporation business, today announced that it has developed a new forensic testing kit designed to improve DNA evidence analysis and streamline the processing of sexual assault cases. The new Quantifiler^® Duo DNA Quantification Kit was developed to enable forensic laboratories to obtain more predictive and comprehensive information from complicated DNA evidence earlier in the testing process, helping to improve results from sexual assault cases and other challenging samples that previously yielded limited or no results.

According to feedback from forensic laboratories surveyed by Applied Biosystems, a high percentage of DNA samples submitted to forensic laboratories are related to sexual assault cases. These samples are often challenging, particularly because of the mixtures of male and female DNA. As a result, the recovery of probative information is limited in approximately 15-20 per cent of sexual assault cases.

With the introduction of the Quantifiler Duo kit, forensic laboratories can obtain more comprehensive information than conventional methods in a single, highly sensitive quantification reaction. The new kit simultaneously provides a quantitative and qualitative assessment of total human and human male DNA and more accurately estimates the quantity of DNA in degraded samples. This efficiently provides the male-to-female DNA mixture ratio, guides selection of the optimal DNA profiling chemistry kit and is expected to increase analysis success rates. Overall, the Quantifiler Duo kit streamlines and integrates the forensic DNA workflow to maximise recovery of results from sexual assault cases and other challenging samples.

The improved workflow enabled by the Quantifiler Duo kit can impact the outcome of complex criminal cases. Laboratories can now efficiently detect low amounts of male DNA mixed with high quantities of female DNA and compare that to the total amount of DNA in each sample. The San Diego Police Department (SDPD) forensic laboratory, an early user, is currently validating and planning to add the Quantifiler Duo kit into its workflow to better assess the characteristics for each DNA sample and obtain information to indicate which DNA profiling chemistry should be used in subsequent analyses: a standard short tandem repeat (STR) kit or a male-specific STR (Y-STR) kit. The ability to obtain more detailed information prior to DNA profiling enables the SDPD analysts to improve results and reduce the need for repeat analysis.

“We have been successful using the Quantifiler Duo kit and obtaining more precise information from samples that contain mixed gender DNA,” said Patrick O’Donnell, the supervising criminalist at the San Diego Police Department’s forensic laboratory. “Having the information about the characteristics of a piece of DNA evidence at the beginning of the testing process can be very powerful for guiding the forensic workflow toward better results in less time.”

Applied Biosystems is a global leader in the development and commercialisation of instrument-based systems, consumables, software and services for the life science market. It is the leader in forensic DNA technologies, providing complete workflow solutions for human identification testing, including instrument systems, reagents and software. The new Quantifiler Duo kit was developed to enable forensic laboratories to obtain more accurate predictive results that improve the overall workflow. This improved workflow can benefit testing of all DNA sample types; however, it is expected to have the most significant impact on sexual assault cases.

The Quantifiler Duo kit contains chemistry reagents that are used on an Applied Biosystems real-time PCR system to amplify, detect and quantify the DNA contained in a sample, guiding STR chemistry selection as the next step in the analysis workflow. When the kit detects a low quantity of male DNA mixed with a high quantity of female DNA, a male-specific DNA kit, or a Y-STR kit – the Applied Biosystems AmpFℓSTR^® Yfiler^® PCR Amplification Kit – is recommended as a more effective means to obtain results in sexual assault analysis. When the Quantifiler Duo kit indicates that a DNA sample is compromised, a specialised mini-STR kit – the Applied Biosystems AmpFℓSTR MiniFiler™ PCR Amplification Kit – is recommended in conjunction with a standard STR kit to obtain results.

“Complicated DNA evidence should not stop forensic laboratories from getting the informative results they need to help law enforcement investigators solve crimes,” said Leonard Klevan, PhD, president for Applied Biosystems’ applied markets division. “Applied Biosystems is delivering the new Quantifiler Duo technology to create an integrated workflow which more quickly uncovers critical information for improved analysis of sexual assaults and other challenging cases.”

The Quantifiler Duo DNA Quantification Kit is expected to be available in spring 2008. For more information about the kit, please visit the article webpage.