Breakthrough Forensic Software Is Becoming the Norm
Celebrating its fifth anniversary of use in live casework, STRmix™ has moved from being an experimental technology to the broadly accepted norm in cases in which a sophisticated forensic software is required to resolve mixed DNA profiles previously thought to be too complex to interpret.
Twenty-nine U.S. labs including numerous local, state, and federal agencies now routinely use STRmix™ when resolving DNA profiles. This includes everything from the recently announced Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) and the U.S. Army Criminal Investigation Laboratory to state and local agencies such as the Michigan State Police, Texas Department of Public Safety, and the California Department of Justice.
An additional 14 laboratories in Australia, England, Scotland, Republic of Ireland, Canada, and New Zealand are using STRmix™.
Earlier this year, the Federal Bureau of Investigation (FBI) published its validation of STRmix™ for use on mixtures of up to five persons. Noting that STRmix™ offers numerous advantages over historical methods of DNA profile analysis and has greater statistical power for estimating evidentiary weight – all of which can be used reliably in human identification testing – the FBI began using STRmix™ in its casework in December 2015.
Another 51 U.S. labs are currently at various stages of STRmix™ installation, validation, and training.
“In five short years, DNA evidence interpreted with STRmix™ has been successfully used in numerous U.S. court cases, while there have been at least 13 successful admissibility hearings for STRmix™,” says John Buckleton DSc, FRSNZ, Forensic Scientist at the New Zealand Institute of Environmental Science and Research (ESR).
Buckleton, who developed STRmix™ in collaboration with ESR’s Jo-Anne Bright and Duncan Taylor from Forensic Science South Australia (FSSA), adds, “Since 2012, STRmix™ has been used to interpret DNA evidence in thousands of cases internationally.”
FSSA Director Chris Pearman notes, “STRmix™ has greatly assisted in enabling FSSA to provide high-quality evidentiary and investigative information to the South Australia Police. With the use of STRmix™, complex mixed profiles can be deconvoluted and searched against the DNA database, generating 10 times the investigative information we could previously provide to police investigators.”
ESR recently launched an upgraded version of STRmix™ after a full year of technical development and testing. STRmix™ v2.5 contains a number of powerful new features designed to significantly improve functionality, speed, memory, and ease of use, including: multi-kit functionality, enabling interpretation of DNA profiles from different test kits; a likelihood ratio (LR) batcher tool, allowing users to calculate multiple LRs from multiple reference inputs to a previously run deconvolution; and a combined DNA Index System (CODIS) report.