New version of STRmix™ allows more complex profiles to be interpreted faster

A new version of STRmix™, groundbreaking forensic software used to resolve mixed DNA profiles previously considered too complex to interpret, will be launched today following nearly a year of extensive development and testing. 

STRmix™ Version 2.8 features a top-down approach that allows users to set the number of major contributors to a mixed DNA profile in which there is interest, and then obtain a likelihood ratio (LR) only for those contributors.  This approach will enable users to tackle more complex profiles faster. 

“The top-down approach incorporated into STRmix™ v2.8 is in direct response to recommendations made by forensic labs to better address the on-the-job needs they regularly encounter,” says John Buckleton DSc, FRSNZ, Forensic Scientist at the New Zealand Institute of Environmental Science and Research (ESR) and one of the developers of STRmix™. “Ultimately, this allows high through-put screening of the profile to provide investigative intelligence regarding the major contributors in complex mixtures.” 

The new version of STRmix™ also contains improved modelling and memory usage features. 

STRmix™ Version 2.8 comes nearly a year to the day after the introduction of Version 2.7. Building on previous versions of the software, STRmix™ v2.7 featured the addition of a variable number of contributors (varNOC) for multi-kits and the ability to compare two or more DNA mixtures to find a common contributor. 

Since its introduction in 2012, STRmix™ has proven to be highly effective in producing usable, interpretable, and admissible DNA results in a wide range of criminal cases, including violent crime and sexual assault cases. It has also been instrumental in helping to solve cold cases in which evidence originally was dismissed as inconclusive. 

“Demand for STRmix™ has been extremely high due to the critical role it plays in helping to solve crimes and excluding individuals who have been wrongly associated as the source of crime scene evidence,” explains Dr. Buckleton. 

To date, STRmix™ has been used to interpret DNA evidence in more than 160,000 cases worldwide. That number includes numerous U.S. court cases, including at least 37 successful admissibility hearings. 

In addition to the U.S. agencies currently employing STRmix™ in criminal investigations, the software is now in various stages of installation, validation, and training in more than 60 other organizations.

The team that created STRmix™ recently launched two other products. DBLR™, an application used with STRmix™, allows users to undertake superfast database searches, visualize the value of their DNA mixture evidence, and carry out mixture to mixture matches.

FaSTR™ DNA, meanwhile, is expert forensic software that rapidly analyzes DNA profiles and assigns a Number of Contributors (NoC) estimate. Designed by scientists for scientists, FaSTR™ DNA combines an intuitive, user-friendly graphical interface with easily understandable and laboratory-customizable rules to expedite the analysis of raw data generated by genetic analyzers and standard profiling kits. FaSTR™ DNA also implements the use of artificial neural networks for peak classification independent of and in parallel to the forensic analyst.

Alongside STRmix™, FaSTR™ DNA and DBLR™ complete the full workflow from analysis to interpretation and database matching.