Software developed in New Zealand that has contributed to identifying suspects in tens of thousands of criminal cases
around the world has won the 2018 Prime Minister’s $500,000 Science Prize.
A team of scientists at the Institute of Environmental Science and Research (ESR) receives New Zealand’s most valuable
science prize for the development of STRmix™, expert scientific software that is used to interpret DNA material from a
crime scene that comes from multiple individuals.
Before STRmix™ started being used in case work in New Zealand in 2012, says ESR Senior Scientist Dr Jo-Anne Bright,
there was a lot of evidential material wasted because many mixed DNA profiles were too complicated to analyse.
“At a lot of crime scenes, particularly sexual assaults, you have samples from the victim and also from the offender,
along with mixtures on clothing that might contain DNA from various people.
“Before STRmix™ existed, we didn’t interpret a lot of these mixtures. Following its introduction in New Zealand, we saw
a 30 to 50 percent improvement in our DNA profiling success rate, with the rates getting better the more complicated the
“Turnaround times are also a lot quicker. Before STRmix™, we spent a lot of time interpreting a profile with a pen,
paper and a calculator. Now we can just load it up on the software and go onto other things while it does the
The resulting data can then be compared to DNA on databases of known individuals or to individual suspects.
STRmix™ is now the number one software for the interpretation of DNA profiles internationally and is routinely used in
case work by more than 40 laboratories around the world. Many of those are in Australia and North America but the
product is also being used in Asia, the Middle East and the United Kingdom.
STRmix™ Manager Bjorn Sutherland, says that rapid take up is testament to the quality of the scientific research carried
out by the 16-member ESR team that developed and continues to advance and support the product.
“The research is world-leading and acknowledged as such internationally. But it’s about more than the software—STRmix
also requires extensive training, support and mentoring while forensic laboratories do the validation required to use it
in criminal case work. We’ve come up with a model that brings all those components together,” he says.
STRmix™ was born out of a crisis in 2009 when an Australian laboratory was forced to close after realising it had been
incorrectly using software to interpret DNA for case work.
Dr John Buckleton, a principal scientist at ESR and one of the world’s leading researchers
in forensic evidence interpretation, worked with Dr Bright and Dr Duncan Taylor from Forensic
Science South Australia to develop a tool that laboratories could use to accurately analyse complex DNA profiles from
crime scenes and reliably use the results in court cases.
STRmix™ was introduced into New Zealand and South Australia in 2012, with the database search function piloted in two
New Zealand Police districts the same year and rolled out to all districts a year later. After two years, 110 cases had
been matched on the database resulting in 93 hits to suspects.
The STRmix™ team says as a conservative estimate, the software has now been used to interpret mixed DNA in more than
100,000 cases worldwide.
Dr Buckleton says: “It has been a great honour to work with Duncan Taylor and Jo-Anne Bright and now the wider STRmix™
team on this project. We have influenced, for the better, forensic DNA analysis in much of the English-speaking world
and to some extent elsewhere.”
Dr Bright says ESR maintains its edge in what is a highly competitive environment by providing a product that is
innovative and trusted by forensic scientists.
“We are fully transparent so all the algorithms supporting the software have been published (in over 40 articles in
peer-reviewed scientific journals). That, along with the expert training we provide, gives laboratories confidence to
adopt the software.”
Dr Bright says the ESR team behind STRmix™ is both proud and passionate. “A lot of us are former forensic scientists so
we used to work in laboratories on the type of casework STRmix™ is designed for, and we have a real sense of the
importance of being involved in solving crimes.
“DNA profile analysis is a really powerful tool for identifying individuals as possible suspects but it’s also important
for being able to exclude or exonerate an individual as well.”
Mr Sutherland says the STRmix™ team is hugely proud to have won the Prime Minister’s Science Prize.
“We have an agile, hardworking and innovative scientific team whose work over the last eight years has, in some
respects, been under the radar because it’s been so internationally focused.
“This is fantastic recognition of what we have been able to achieve.”
The prize money will be used to further develop the science behind STRmix™ by investigating the use of new technologies,
such as artificial intelligence or machine learning, to continually improve what can be determined from mixed DNA
profiles and to speed up turnaround times.
The development of STRmix™ has been funded by ESR with support from the Kiwi Innovation Network’s (KiwiNet) PreSeed